Exhibit 1.1

Aon North America, Inc.

Aon Global Holdings plc

Aon plc

Aon Corporation

Aon Global Limited

$2,000,000,000 5.350% Senior Notes due 2029

$3,000,000,000 5.625% Senior Notes due 2031

$2,000,000,000 5.800% Senior Notes due 2033

$2,750,000,000 5.950% Senior Notes due 2036

$1,000,000,000 6.100% Senior Notes due 2038

$750,000,000 6.450% Senior Notes due 2046

$2,000,000,000 6.450% Senior Notes due 2056

UNDERWRITING AGREEMENT

September 14, 2026

Citigroup Global Markets Inc.

BofA Securities, Inc.

Morgan Stanley & Co. LLC

Wells Fargo Securities, LLC

HSBC Securities (USA) Inc.

As representatives (the “Representatives”) of the several underwriters listed in Exhibit A hereto

388 Greenwich Street

New York, New York 10013

One Bryant Park

New York, New York 10036

1585 Broadway

New York, New York 10036

550 South Tryon Street, 5th Floor

Charlotte, North Carolina 28202

66 Hudson Boulevard

New York, New York 10001

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Ladies and Gentlemen:

For purposes of this Agreement:

“430B Information” means information included in a prospectus then deemed to be a part of the Registration Statement pursuant to Rule 430B(e) or retroactively deemed to be a part of the Registration Statement pursuant to Rule 430B(f).

“430C Information” means information included in a prospectus then deemed to be a part of the Registration Statement pursuant to Rule 430C.

“Act” means the Securities Act of 1933, as amended.

“Applicable Time” means 4:15 p.m. (New York City time) on the date of this Agreement.

“Closing Date” has the meaning set forth in Section 3 hereof.

“Commission” means the Securities and Exchange Commission.

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“Exchange Act” means the Securities Exchange Act of 1934, as amended.

“Final Prospectus” means the Statutory Prospectus that discloses the public offering price, other 430B Information and other final terms of the Securities, and otherwise satisfies Section 10(a) of the Act.

“General Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being so specified in Exhibit B to this Agreement.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433, relating to the Securities in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Issuers’ records pursuant to Rule 433(g).

“Limited Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is not a General Use Issuer Free Writing Prospectus.

“Rules and Regulations” means the rules and regulations of the Commission.

“Securities Laws” means, collectively, the Sarbanes-Oxley Act of 2002, as amended, and all rules and regulations promulgated thereunder or implementing the provisions thereof (“Sarbanes-Oxley”), the Act, the Exchange Act, the Trust Indenture Act, the Rules and Regulations, the auditing principles, rules, standards and practices applicable to auditors of “issuers” (as defined in Sarbanes-Oxley) promulgated or approved by the Public Company Accounting Oversight Board and, as applicable, the rules of The New York Stock Exchange (“Exchange Rules”).

“Statutory Prospectus” with reference to any particular time means the prospectus relating to the Securities that is included in the Registration Statement immediately prior to that time, including all 430B Information and all 430C Information with respect to the Registration Statement. For purposes of the foregoing definition, 430B Information shall be considered to be included in the Statutory Prospectus only as of the actual time that such form of prospectus (including a prospectus supplement) is filed with the Commission pursuant to Rule 424(b) and not retroactively.

“Trust Indenture Act” means the Trust Indenture Act of 1939, as amended.

Unless otherwise specified, a reference to a “rule” is to the indicated rule under the Act.

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The Issuers will deliver the Securities to or as instructed by the Representatives for the accounts of the several Underwriters in a form reasonably acceptable to the Representatives against payment of the applicable Purchase Price by the Underwriters in Federal (same day) funds by wire transfer to an account at a bank acceptable to the Representatives through the offices of Davis Polk & Wardwell LLP, 450 Lexington Avenue, New York, New York 10017, at 10:00 a.m., New York time, on September 17, 2026, or at such other time not later than seven full business

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days thereafter as the Representatives and the Issuers determine, such time being herein referred to as the “Closing Date”. For purposes of Rule 15c6-1 under the Exchange Act, the Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Securities sold pursuant to the offering. The Securities so to be delivered or evidence of their issuance will be made available for inspection at the above office of Davis Polk & Wardwell LLP at least 24 hours prior to the Closing Date.

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The Issuers and the Guarantors will furnish the Representatives with such conformed copies of such opinions, certificates, letters and documents as the Representatives may reasonably request. The Representatives may in their sole discretion waive on behalf of the Underwriters compliance with any conditions to the obligations of the Underwriters hereunder.

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provided, however, that any notice to an Underwriter pursuant to Section 8 will be mailed, delivered or telegraphed and confirmed to such Underwriter.

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“BHC Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted in accordance with, 12 U.S.C. § 1841(k).

“Covered Entity” means any of the following:

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“Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable.

“U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

“UK Bail-in Legislation” means Part I of the UK Banking Act 2009 and any other law or regulation applicable in the UK relating to the resolution of unsound or failing banks, investment firms or other financial institutions or their affiliates (otherwise than through liquidation, administration or other insolvency proceedings).

“UK Bail-in Liability” means a liability in respect of which the UK Bail-in Powers may be exercised.

“UK Bail-in Powers” means the powers under the UK Bail-in Legislation to cancel, transfer or dilute shares issued by a person that is a bank or investment firm or affiliate of a bank or investment firm, to cancel, reduce, modify or change the form of a liability of such a person or any contract or instrument under which that liability arises, to convert all or part of that liability into shares, securities or obligations of that person or any other person, to provide that any such contract or instrument is to have effect as if a right had been exercised under it or to suspend any obligation in respect of that liability.

[Signature Pages Follow.]

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If the foregoing is in accordance with the Representatives’ understanding of our agreement, kindly sign and return to us your counterpart hereof, whereupon it will become a binding agreement among the Issuers, the Guarantors and the several Underwriters in accordance with its terms.

[Signature Page to Underwriting Agreement]

The foregoing Agreement is hereby confirmed and accepted as of the date first above written.

[Signature Page to Underwriting Agreement]

The foregoing Agreement is hereby confirmed and accepted as of the date first above written.

[Signature Page to Underwriting Agreement]

The foregoing Agreement is hereby confirmed and accepted as of the date first above written.

[Signature Page to Underwriting Agreement]

The foregoing Agreement is hereby confirmed and accepted as of the date first above written.

[Signature Page to Underwriting Agreement]

The foregoing Agreement is hereby confirmed and accepted as of the date first above written.

[Signature Page to Underwriting Agreement]

EXHIBIT A

Exhibit A-1

EXHIBIT B

“General Use Issuer Free Writing Prospectus” means:

The pricing term sheet, dated September 14, 2026, a copy of which is attached hereto as Annex B-1.

The following information is also included in the General Disclosure Package:

None.

Exhibit B-1

ANNEX B-1

Aon North America, Inc. and Aon Global Holdings plc

$2,000,000,000 5.350% SENIOR NOTES DUE 2029 (the “2029 Notes”)

$3,000,000,000 5.625% SENIOR NOTES DUE 2031 (the “2031 Notes”)

$2,000,000,000 5.800% SENIOR NOTES DUE 2033 (the “2033 Notes”)

$2,750,000,000 5.950% SENIOR NOTES DUE 2036 (the “2036 Notes”)

$1,000,000,000 6.100% SENIOR NOTES DUE 2038 (the “2038 Notes”)

$750,000,000 6.450% SENIOR NOTES DUE 2046 (the “2046 Notes”)

$2,000,000,000 6.450% SENIOR NOTES DUE 2056 (the “2056 Notes”)

(together, the “Notes”)

PRICING TERM SHEET

Terms Applicable to the Notes

Exhibit B-1-1

Exhibit B-1-2

Exhibit B-1-3

Exhibit B-1-4

Exhibit B-1-5

*Note: An explanation of the significance of ratings may be obtained from the rating agencies. Generally, rating agencies base their ratings on such material and information, and such of their own investigations, studies and assumptions, as they deem appropriate. The rating of the Notes should be evaluated independently from similar ratings of other securities. A credit rating of a security is not a recommendation to buy, sell or hold securities and may be subject to review, revision, suspension, reduction or withdrawal at any time by the assigning rating agency.

**Note: The information in this Pricing Term Sheet supplements the Preliminary Prospectus Supplement and supersedes the information in the Preliminary Prospectus Supplement to the extent inconsistent with the information in the Preliminary Prospectus Supplement. The T+3 settlement cycle specified in this Pricing Term Sheet supersedes the extended settlement language included in the Preliminary Prospectus Supplement.

The issuers and the guarantors have filed a registration statement, including a prospectus, with the U.S. Securities and Exchange Commission (the “SEC”) for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuers and the guarantors have filed with the SEC for more complete information about the issuers, the guarantors and this offering. You may get these documents for free by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, the Joint Book-Running Managers in the offering will arrange to send you the prospectus if you request it by contacting Citigroup Global Markets Inc. at 1-800-831-9146, BofA Securities, Inc. at 1-800-294-1322, HSBC Securities (USA) Inc. at 1-866-811-8049, Morgan Stanley & Co. LLC at prospectus@morganstanley.com or Wells Fargo Securities, LLC at 1-800-645-3751.

Any disclaimers or other notices that may appear below are not applicable to this communication and should be disregarded (other than any statement relating to the identity of the legal entity authorizing or sending this communication in a non-U.S. jurisdiction). Such disclaimers or other notices were automatically generated as a result of this communication having been sent via Bloomberg or another e-mail system.

Exhibit B-1-6

EXHIBIT C

Significant Subsidiaries

Exhibit C-1

Exhibit 4.2

AON NORTH AMERICA, INC.

AON GLOBAL HOLDINGS PLC

SECOND INDENTURE SUPPLEMENT

DATED AS OF SEPTEMBER 17, 2026

TO

THE INDENTURE

DATED AS OF MARCH 1, 2024

THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.

TRUSTEE

DEBT SECURITIES

THIS SECOND INDENTURE SUPPLEMENT (the “Second Indenture Supplement”), is dated as of September 17, 2026, among Aon North America, Inc., a corporation duly organized and existing under the laws of the State of Delaware (hereinafter sometimes called the “Company”, which term includes any successor Person under the Indenture hereinafter referred to), Aon Global Holdings plc, a public limited company duly organized and existing under the laws of England and Wales (hereinafter sometimes called “AGH” or the “Co-Issuer,” which term includes any successor Person under the Indenture hereinafter referred to, and, together with the Company, the “Issuers”), Aon plc, a public limited company duly organized and existing under the laws of Ireland (hereinafter sometimes called “Aon plc”), Aon Corporation, a corporation duly organized and existing under the laws of the State of Delaware (hereinafter sometimes called “Aon Corporation”), Aon Global Limited, a private limited company duly organized and existing under the laws of England and Wales (hereinafter sometimes called “AGL” and, together with Aon plc and Aon Corporation, the “Guarantors” and each, a “Guarantor”), and The Bank of New York Mellon Trust Company, N.A., a national banking association duly incorporated and existing under the laws of the United States of America (hereinafter sometimes called the “Trustee”, which term shall include any successor trustee appointed pursuant to Article Seven of the Base Indenture (as defined below)), and is a supplemental indenture supplementing the Base Indenture.

WITNESSETH:

WHEREAS, the Company, AGH, the Guarantors and the Trustee executed and delivered an indenture, dated as of March 1, 2024 (the “Base Indenture” and, together with this Second Indenture Supplement, the “Indenture”), to provide for the issuance from time to time for their lawful purposes debt securities (hereinafter called “Securities” or, in the singular, a “Security”) evidencing their unsecured indebtedness.

WHEREAS, Section 10.01 of the Base Indenture provides that a supplemental indenture may be entered into by the Issuers, Aon plc, Aon Corporation and AGL when authorized by or pursuant to a Board Resolution, and the Trustee without the consent of any Holders to make provisions to establish the form or terms of Securities of any series as permitted by Sections 2.01 and 2.03 of the Base Indenture.

WHEREAS, solely with respect to the application of such provisions to the Notes, the Issuers and the Guarantors desire to (i) effect that the Company and AGH co-issue the Notes, which are joint and several obligations of each Issuer, (ii) effect such guarantees by each of Aon plc, Aon Corporation and AGL, (iii) establish the form and terms of the Notes without the consent of any Holders as permitted by Sections 2.01 and 2.03 of the Base Indenture and (iv) execute a supplemental indenture to the Base Indenture pursuant to Section 10.01 thereof to effect the foregoing.

WHEREAS, each of the Company, AGH, Aon plc, Aon Corporation and AGL represents that all acts and things necessary to make this Second Indenture Supplement a valid and binding supplemental indenture have been done and performed, and the execution of this Second Indenture Supplement as a supplemental indenture to the Base Indenture by each of the Company, AGH, Aon plc, Aon Corporation and AGL has in all respects been duly authorized, and each of the Company, AGH, Aon plc, Aon Corporation and AGL, in the exercise of legal rights and power in it vested, is executing this Second Indenture Supplement.

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NOW, THEREFORE, for and in consideration of the foregoing premises, the Issuers, the Guarantors and the Trustee mutually covenant and agree for the equal and proportionate benefit of the respective Holders from time to time of the Notes as follows:

ARTICLE I

Defined Terms

Section 1.01. Defined Terms . Except as otherwise expressly provided in this Second Indenture Supplement or in the respective form of Note attached as Exhibit A hereto or otherwise clearly required by the context hereof or thereof, all capitalized terms used and not defined in this Second Indenture Supplement that are defined in the Base Indenture shall have the meanings assigned to them in the Base Indenture. For all purposes of this Second Indenture Supplement only:

“2029 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $2,000,000,000 aggregate principal amount of 5.350% senior notes due 2029. For purposes of the Indenture, the 2029 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2029 Notes” shall include the 2029 Notes initially issued on the Closing Date and any other 2029 Notes issued after the Closing Date.

“2031 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $3,000,000,000 aggregate principal amount of 5.625% senior notes due 2031. For purposes of the Indenture, the 2031 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2031 Notes” shall include the 2031 Notes initially issued on the Closing Date and any other 2031 Notes issued after the Closing Date.

“2033 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $2,000,000,000 aggregate principal amount of 5.800% senior notes due 2033. For purposes of the Indenture, the 2033 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2033 Notes” shall include the 2033 Notes initially issued on the Closing Date and any other 2033 Notes issued after the Closing Date.

“2036 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $2,750,000,000 aggregate principal amount of 5.950% senior notes due 2036. For purposes of the Indenture, the 2036 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2036 Notes” shall include the 2036 Notes initially issued on the Closing Date and any other 2036 Notes issued after the Closing Date.

“2038 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $1,000,000,000 aggregate principal amount of 6.100% senior notes due 2038.

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For purposes of the Indenture, the 2038 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2038 Notes” shall include the 2038 Notes initially issued on the Closing Date and any other 2038 Notes issued after the Closing Date.

“2046 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $750,000,000 aggregate principal amount of 6.450% senior notes due 2046. For purposes of the Indenture, the 2046 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2046 Notes” shall include the 2046 Notes initially issued on the Closing Date and any other 2046 Notes issued after the Closing Date.

“2056 Notes” means a new series of Securities to be co-issued by the Company and AGH to be known as $2,000,000,000 aggregate principal amount of 6.450% senior notes due 2056. For purposes of the Indenture, the 2056 Notes shall constitute a single series of Securities under the Indenture and shall vote together to the extent so provided therein. For all purposes of this Second Indenture Supplement, the term “2056 Notes” shall include the 2056 Notes initially issued on the Closing Date and any other 2056 Notes issued after the Closing Date.

“Base Indenture” has the meaning set forth in the recitals hereof.

“Closing Date” means September 17, 2026.

“Global Securities Legend” means the legend set forth on the form of Note attached as Exhibit A hereto.

“Guarantors” has the meaning set forth in the recitals hereof.

“Indenture” has the meaning set forth in the recitals hereof.

“Interest Payment Date” means, as applicable, (i) a 2029 Notes Interest Payment Date, (ii) a 2031 Notes Interest Payment Date, (iii) a 2033 Notes Interest Payment Date, (iv) a 2036 Notes Interest Payment Date, (v) a 2038 Notes Interest Payment Date, (vi) a 2046 Notes Interest Payment Date and (vii) a 2056 Notes Interest Payment Date (in each case, as defined in Section 2.02(d)).

“Merger Agreement” means the agreement and plan of merger, dated as of August 30, 2026, by and among Aon plc, the Company, Merger Sub, USI, and Uno Aggregator II L.P., a Delaware limited partnership.

“Merger Sub” means Cortlandt Acquisition Corp., a Delaware corporation and an indirect, wholly owned subsidiary of Aon plc.

“USI” means USI Advantage Corp., a Delaware corporation.

“USI Acquisition” means the acquisition by the Company of the issued and outstanding equity interests of USI pursuant to the Merger Agreement.

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“USI Acquisition Notes” means, collectively, the 2029 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes, the 2038 Notes and the 2046 Notes.

“Notes” means, collectively, the 2029 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes, the 2038 Notes, the 2046 Notes and the 2056 Notes, in each case co-issued by the Company and AGH and substantially in the form attached hereto as Exhibit A, fully and unconditionally guaranteed as to payment of principal and interest by Aon plc, Aon Corporation and AGL, each designated in Section 2.01 hereof and authenticated and delivered under the Indenture.

“Par Call Date” means (i) August 17, 2029 (the date that is one month prior to the Stated Maturity for the 2029 Notes) for the 2029 Notes, (ii) August 17, 2031 (the date that is one month prior to the Stated Maturity for the 2031 Notes) for the 2031 Notes, (iii) July 17, 2033 (the date that is two months prior to the Stated Maturity for the 2033 Notes) for the 2033 Notes, (iv) June 17, 2036 (the date that is three months prior to the Stated Maturity for the 2036 Notes) for the 2036 Notes, (v) June 17, 2038 (the date that is three months prior to the Stated Maturity for the 2038 Notes) for the 2038 Notes, (vi) March 17, 2046 (the date that is six months prior to the Stated Maturity for the 2046 Notes) for the 2046 Notes and (vii) March 17, 2056 (the date that is six months prior to the Stated Maturity for the 2056 Notes) for the 2056 Notes.

“Regular Record Date” means, as applicable, (i) a 2029 Regular Record Date, (ii) a 2031 Regular Record Date, (iii) a 2033 Regular Record Date, (iv) a 2036 Regular Record Date, (v) a 2038 Regular Record Date, (vi) a 2046 Regular Record Date and (vii) a 2056 Regular Record Date (in each case, as defined in Section 2.02(d)).

“Stated Maturity” has the meaning set forth in Section 2.02 hereof.

“Treasury Rate” means, with respect to any redemption date, the yield determined by the Issuers in accordance with the following two paragraphs:

The Treasury Rate shall be determined by the Issuers after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third business day preceding the redemption date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as “Selected Interest Rates (Daily)—H.15” (or any successor designation or publication) (“H.15”) under the caption “U.S. government securities–Treasury constant maturities–Nominal” (or any successor caption or heading). In determining the Treasury Rate, the Issuers shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the applicable Par Call Date (the “Remaining Life”); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the applicable Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the redemption date.

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If on the third business day preceding the redemption date H.15 is no longer published, the Issuers shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second business day preceding such redemption date of the United States Treasury security maturing on, or with a maturity that is closest to, the applicable Par Call Date, as applicable. If there is no United States Treasury security maturing on the applicable Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the applicable Par Call Date and one with a maturity date following the applicable Par Call Date, the Issuers shall select the United States Treasury security with a maturity date preceding the applicable Par Call Date. If there are two or more United States Treasury securities maturing on the applicable Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Issuers shall select from among these two or more United States Treasury securities the United States Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places. The Trustee shall have no responsibility to calculate, or to verify the Issuers’ calculation, of any redemption price.

“Trustee” has the meaning set forth in the preamble hereof.

The parties hereto acknowledge that certain terms are defined in both the Base Indenture and in this Second Indenture Supplement. The parties hereto hereby agree that, unless otherwise expressly stated or the context otherwise requires, any term which is defined in either the Base Indenture or this Second Indenture Supplement, when used with respect to or in the respective certificates evidencing the Notes, shall have the meaning set forth in this Second Indenture Supplement.

ARTICLE II

Terms of the Notes

Section 2.01. Establishment of the Notes .

(a) There is hereby authorized and established (i) a series of Securities designated the 5.350% senior notes due 2029, limited in aggregate principal amount to $2,000,000,000, (ii) a series of Securities designated the 5.625% senior notes due 2031, limited in aggregate principal amount to $3,000,000,000, (iii) a series of Securities designated the 5.800% senior notes due 2033, limited in aggregate principal amount to $2,000,000,000, (iv) a series of Securities designated the 5.950% senior notes due 2036, limited in aggregate principal

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amount to $2,750,000,000, (v) a series of Securities designated the 6.100% senior notes due 2038, limited in aggregate principal amount to $1,000,000,000, (vi) a series of Securities designated the 6.450% senior notes due 2046, limited in aggregate principal amount to $750,000,000 and (vii) a series of Securities designated the 6.450% senior notes due 2056, limited in aggregate principal amount to $2,000,000,000 (provided that the foregoing limitations on the aggregate principal amount of Notes of each series shall not apply to Notes authenticated and delivered upon registration of transfer of, or in exchange for, or in lieu of, other Notes of such series pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture); provided that the Issuers may, from time to time, without notice to or consent of Holders or beneficial owners of the Outstanding Notes of any series, increase the aggregate principal amount of Outstanding Notes of any series pursuant to Section 2.01 of the Indenture in compliance with the procedures set forth in the Indenture, including Sections 2.03 and 2.04 thereof, by issuing Additional Securities having the same ranking, interest rate, maturity and other terms (except for the issue date, public offering price and, in some cases, the first Interest Payment Date and the date from which interest shall begin to accrue) as the Notes of such series then Outstanding; provided, further, that any such Additional Securities will constitute part of the same series as the Notes of such series issued on the Closing Date; and provided, further, that if such Additional Securities are not fungible for U.S. federal income tax purposes with the Notes of such series issued on the Closing Date, then such Additional Securities will have a separate CUSIP number.

(b) The form and terms of each series of Notes have been established pursuant to authority duly granted by the Board Resolutions of the Company and AGH, adopted on August 30, 2026 and September 11, 2026, respectively (together, the “Board Resolutions”), in accordance with Section 2.03 of the Indenture, and the Corporate Secretaries of the Company and AGH have certified that the Board Resolutions have been duly adopted by the applicable board of directors and are in full force and effect on the date of such certification.

Section 2.02. Terms of the Notes . The following terms relate to the applicable series of Notes:

(a) The 2029 Notes hereby established are a series of Securities having the title “5.350% senior notes due 2029 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A. The 2031 Notes hereby established are a series of Securities having the title “5.625% senior notes due 2031 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A. The 2033 Notes hereby established are a series of Securities having the title “5.800% senior notes due 2033 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A. The 2036 Notes hereby established are a series of Securities having the title “5.950% senior notes due 2036 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as

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provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A. The 2038 Notes hereby established are a series of Securities having the title “6.100% senior notes due 2038 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A. The 2046 Notes hereby established are a series of Securities having the title “6.450% senior notes due 2046 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A. The 2056 Notes hereby established are a series of Securities having the title “6.450% senior notes due 2056 with full and unconditional guarantees as to payment of principal and interest by Aon plc, Aon Corporation and Aon Global Limited,” the terms and provisions of which are as provided for in Section 2.01 of the Indenture with the further terms and provisions as set forth in the form of the Notes attached hereto as Exhibit A.

(b) The initial aggregate principal amount of the 2029 Notes that may be issued, authenticated and delivered under the Indenture (except for 2029 Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2029 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2029 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $2,000,000,000. The initial aggregate principal amount of the 2031 Notes that may be issued, authenticated and delivered under the Indenture (except for 2031 Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2031 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2031 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $3,000,000,000. The initial aggregate principal amount of the 2033 Notes that may be issued, authenticated and delivered under the Indenture (except for 2033 Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2033 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2033 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $2,000,000,000. The initial aggregate principal amount of the 2036 Notes that may be issued, authenticated and delivered under the Indenture (except for 2036 Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2036 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2036 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $2,750,000,000. The initial aggregate principal amount of the 2038 Notes that may be issued, authenticated and delivered under the Indenture (except for 2038 Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2038 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2038 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $1,000,000,000. The initial aggregate principal amount of the 2046 Notes that may be issued, authenticated and delivered under the Indenture (except for 2046 Notes

7

authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2046 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2046 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $750,000,000. The initial aggregate principal amount of the 2056 Notes that may be issued, authenticated and delivered under the Indenture (except for 2056 Notes authenticated and delivered upon registration of, transfer of, or in exchange for, or in lieu of, other 2056 Notes pursuant to Sections 2.05, 2.06, 2.07, 3.03, 6.01 or 10.04 of the Indenture or 2056 Notes authenticated and delivered as Additional Securities pursuant to Section 2.01 of the Base Indenture and Section 2.01 of this Second Indenture Supplement) is $2,000,000,000.

(c) The Stated Maturity on which the principal of the 2029 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2029. The Stated Maturity on which the principal of the 2031 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2031. The Stated Maturity on which the principal of the 2033 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2033. The Stated Maturity on which the principal of the 2036 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2036. The Stated Maturity on which the principal of the 2038 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2038. The Stated Maturity on which the principal of the 2046 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2046. The Stated Maturity on which the principal of the 2056 Notes shall be due and payable (unless earlier redeemed) shall be September 17, 2056.

(d) The principal of the 2029 Notes shall bear interest at the rate of 5.350% per annum, which interest shall accrue from the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2029 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2029 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2029 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day. The principal of the 2031 Notes shall bear interest at the rate of 5.625% per annum, which interest shall accrue from the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2031 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2031 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2031 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day. The principal of the 2033 Notes shall bear interest at the rate of 5.800% per annum, which interest shall accrue from the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2033 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2033 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2033 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day. The principal of the 2036 Notes shall

8

bear interest at the rate of 5.950% per annum, which interest shall accrue from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2036 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2036 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2036 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day. The principal of the 2038 Notes shall bear interest at the rate of 6.100% per annum, which interest shall accrue from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2038 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2038 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2038 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day. The principal of the 2046 Notes shall bear interest at the rate of 6.450% per annum, which interest shall accrue from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2046 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2046 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2046 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day. The principal of the 2056 Notes shall bear interest at the rate of 6.450% per annum, which interest shall accrue from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, and if no interest has been paid or duly provided for, from and including September 17, 2026, payable semi-annually in arrears on March 17 and September 17 (each, a “2056 Notes Interest Payment Date”) in each year, commencing March 17, 2027, to the Persons in whose names the 2056 Notes are registered at the close of business on the March 2 or September 2 immediately preceding such Interest Payment Dates (each, a “2056 Notes Regular Record Date”) regardless of whether such Regular Record Date is a Business Day.

(e) Interest on each series of Notes shall be calculated on the basis of a 360-day year of twelve 30-day months. Except as described below for the first applicable Interest Payment Date, on each applicable Interest Payment Date, the Issuers will pay interest on each series of Notes for the period commencing on (and including) the immediately preceding applicable Interest Payment Date and ending on (and including) the day immediately preceding that Interest Payment Date. On the first applicable Interest Payment Date, the Issuers will pay interest for the period beginning on (and including) the issue date to (but excluding) the first applicable Interest Payment Date. If any Interest Payment Date falls on a day that is not a Business Day, the related interest payment shall be postponed to the next day that is a Business Day, and no interest on such payment shall accrue for the period from and after such Interest Payment Date. If the Stated Maturity or date of earlier redemption falls on a day that is not a Business Day, payment of principal and interest on such series of Notes will be made on the next succeeding day that is a Business Day, and no interest will accrue for the period from and after such Stated Maturity or date of earlier redemption. “Business Day” means any day, other than Saturday or Sunday, that is neither a legal holiday nor a day on which banking institutions are authorized or required by law, regulation or executive order to close in the City of New York.

9

(f) Prior to the applicable Par Call Date with respect to a series of Notes, the Issuers may redeem the Notes of such series, at their option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of the principal amount and rounded to three decimal places) equal to the greater of:

(i) (a) the sum of the present values of the remaining scheduled payments of principal and interest on the Notes being redeemed discounted to the redemption date (assuming the Notes being redeemed matured on the applicable Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate, plus (i) 10 basis points (0.100%), in the case of the 2029 Notes, (ii) 15 basis points (0.150%), in the case of the 2031 Notes, (iii) 15 basis points (0.150%), in the case of the 2033 Notes, (iv) 20 basis points (0.200%), in the case of the 2036 Notes, (v) 20 basis points (0.200%), in the case of the 2038 Notes, (vi) 20 basis points (0.200%), in the case of the 2046 Notes and (vii) 20 basis points (0.200%), in the case of the 2056 Notes, less (b) accrued and unpaid interest to the date of redemption, and

(ii) 100% of the principal amount of the Notes being redeemed; plus, in each case, accrued and unpaid interest on the principal amount of the Notes being redeemed to the redemption date.

(g) On or after the applicable Par Call Date with respect to a series of Notes, the Issuers may redeem the Notes of such series, at their option, in whole or in part, at any time and from time to time, at a redemption price equal to 100% of the principal amount of the Notes being redeemed, plus accrued and unpaid interest thereon to the redemption date.

Notwithstanding the foregoing, installments of interest on Notes being redeemed that are due and payable on interest payment dates falling on or prior to a redemption date will be payable on the interest payment date to the registered holders as of the close of business on the relevant record date according to such Notes and the Indenture.

(h) All payments of interest and principal, including payments made upon any redemption or repurchase of Notes, will be payable in U.S. Dollars.

(i) Each series of Notes is designated, pursuant to Section 2.01 of the Indenture, as being entitled to the benefits of the Guarantees of Aon plc, Aon Corporation and AGL, and Article Fifteen of the Base Indenture shall apply, and inure to the benefit of, each series of Notes.

(j) Each series of Notes is subject to redemption at the option of the Issuers as provided in the form of Note attached hereto as Exhibit A and in the Indenture.

(k) Each series of Notes shall have such other terms and provisions as are set forth in the form of Note attached hereto as Exhibit A (all of which are incorporated by reference in and made a part of this Second Indenture Supplement as if set forth in full at this place).

10

(l) In the event that the USI Acquisition is not consummated on or before the earliest of (i) the later of (x) June 1, 2027 and (y) such later date to which the outside date under the Merger Agreement as in effect on the issue date may be extended in accordance with the terms thereof, (ii) the valid termination of the Merger Agreement (other than in connection with the consummation of the USI Acquisition) and (iii) the Issuers’ determination based on their reasonable judgment (in which case the Issuers will notify the Trustee in writing thereof) that the USI Acquisition will not be consummated (any event described in clause (i), (ii) or (iii), a “Special Mandatory Redemption Event”), the Issuers will be required to redeem all of the outstanding USI Acquisition Notes of each series at a redemption price equal to 101% of the aggregate principal amount of such USI Acquisition Notes, plus accrued and unpaid interest, if any, to, but excluding, the redemption date (the “Special Mandatory Redemption Price”, and such redemption, a “Special Mandatory Redemption”). Upon the occurrence of a Special Mandatory Redemption Event, the Issuers will cause a notice of Special Mandatory Redemption to be transmitted to the Trustee and each holder of the USI Acquisition Notes at its registered address (or electronically delivered or otherwise transmitted in accordance with the depositary’s procedures) promptly, but in any event not later than five Business Days after the occurrence of such Special Mandatory Redemption Event, and will redeem the USI Acquisition Notes on the date specified in such notice (the date so specified, the “Special Mandatory Redemption Date”). The Special Mandatory Redemption Date will be a date selected by the Issuers and set forth in the notice of Special Mandatory Redemption and will be no later than 30 days following the occurrence of the applicable Special Mandatory Redemption Event, but no earlier than the fifth Business Day following the day the notice of Special Mandatory Redemption is transmitted to holders of the USI Acquisition Notes. In no event shall the Trustee be responsible for monitoring the status of the USI Acquisition. If funds sufficient to pay the Special Mandatory Redemption Price of the USI Acquisition Notes on the Special Mandatory Redemption Date are deposited with the Trustee or a paying agent on or before such Special Mandatory Redemption Date, on and after such Special Mandatory Redemption Date, the USI Acquisition Notes will cease to bear interest.

Section 2.03. Denominations . The Notes shall be issued in registered form without interest coupons and only in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof.

Section 2.04. Form . The Notes will be represented by one or more Global Securities. The Notes shall be in substantially the form set forth in Exhibit A hereto with such changes therein as may be authorized by any officer of the Company and AGH executing such Notes by manual, facsimile or electronic signature, such approval to be conclusively evidenced by the execution thereof by such applicable officer.

The terms and provisions contained in each series of Notes shall constitute, and are hereby expressly made, a part of this Second Indenture Supplement, and the Issuers and the Trustee, by their execution and delivery of this Second Indenture Supplement, expressly agree to such terms and provisions and to be bound thereby. However, to the extent any provision of any series of Notes conflicts with the express provisions of this Second Indenture Supplement, the provisions of this Second Indenture Supplement shall govern and be controlling.

Each series of Notes shall be issued as registered Securities without coupons.

11

ARTICLE III

Miscellaneous

Section 3.01. Amendment to Section 4.04—Statement by Officers as to Default . For purposes of the Notes, Section 4.04 of the Base Indenture shall be deleted in its entirety and is hereby replaced and superseded with the following provision:

“Section 4.04. Statement by Officers as to Default.

(a) Either the Company or the Co-Issuer will deliver to the Trustee, on or before a date not more than four months after the end of each fiscal year of the Company or the Co-Issuer, as applicable, ending after the date hereof, an Officers’ Certificate of the Company or the Co-Issuer, as applicable, which shall include the statements provided for in Section 16.04 and stating whether or not to the best knowledge of the signers thereof either the Company or the Co-Issuer is in default in the performance or observance of any of the terms, provisions and conditions of this Indenture to be performed or observed by it and specifying all such defaults and the nature thereof of which it may have knowledge.

(b) The Company and the Co-Issuer, as applicable, will deliver to the Trustee, as soon as practicable upon becoming aware of any default (which word has the meaning of the word “default” as used in Section 6.07) or Event of Default with respect to a particular series of Securities that has occurred and is continuing, a written notice setting forth the details of such default or Event of Default.”

ARTICLE IV

Miscellaneous

Section 4.01. Ratification . This Second Indenture Supplement shall be deemed part of the Base Indenture in the manner and to the extent herein provided. Except as expressly amended hereby, the Base Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect.

Section 4.02. Provisions Binding on Successors . All the covenants, stipulations, promises and agreements in this Second Indenture Supplement contained by or on behalf of the Issuers or the Guarantors shall bind their respective successors and assigns, whether so expressed or not.

Section 4.03. Counterparts . This Second Indenture Supplement and the Global Securities may be executed in any number of counterparts, each of which so executed shall be deemed an original, but all of such counterparts shall together constitute but one and the same instrument. The use of electronic signatures and electronic records (including, without limitation, any contract or other record created, generated, sent, communicated, received, or stored by electronic means) shall be of the same legal effect, validity and enforceability as a manually executed signature or use of a paper- based record-keeping system to the fullest extent permitted by applicable law, including the Federal Electronic Signatures in Global and National Commerce Act, the New York State Electronic Signatures and Records Act, and any other applicable law, including, without limitation, any state law based on the Uniform Electronic Transactions Act or the Uniform Commercial Code.

12

Section 4.04. Governing Law . This Second Indenture Supplement shall be governed by and construed in accordance with the laws of the State of New York, without regard to the principles of conflicts of laws.

Section 4.05. Separability . In case any one or more of the provisions contained in this Second Indenture Supplement or in the Notes shall for any reason be held to be invalid, illegal or unenforceable in any respect, such invalidity, illegality or unenforceability shall not affect any other provisions of this Second Indenture Supplement or of such Notes, but this Second Indenture Supplement and such Notes shall be construed as if such invalid or illegal or unenforceable provision had never been contained herein or therein.

Section 4.06. Trustee . The Trustee makes no representation as to the validity or sufficiency of this Second Indenture Supplement. The recitals contained herein shall be taken as the statements of the Issuers and the Trustee assumes no responsibility for their correctness. The Trustee shall have the right to accept and act upon instructions, including funds transfer instructions (“Instructions”), given pursuant to this Second Indenture Supplement and delivered using Electronic Means; provided, however, that the Issuers shall provide to the Trustee an incumbency certificate listing officers with the authority to provide such Instructions (“Authorized Officers”) and containing specimen signatures of such Authorized Officers, which incumbency certificate shall be amended by the Issuers whenever a person is to be added or deleted from the listing. If the Company or the Co-Issuer elects to give the Trustee Instructions using Electronic Means and the Trustee in its discretion elects to act upon such Instructions, the Trustee’s understanding of such Instructions shall be deemed controlling. Each of the Issuers understands and agrees that the Trustee cannot determine the identity of the actual sender of such Instructions and that the Trustee shall conclusively presume that directions that purport to have been sent by an Authorized Officer listed on the incumbency certificate provided to the Trustee have been sent by such Authorized Officer. The Issuers shall be responsible for ensuring that only Authorized Officers transmit such Instructions to the Trustee and that the Issuers and all Authorized Officers are solely responsible to safeguard the use and confidentiality of applicable user and authorization codes, passwords and/or authentication keys upon receipt by the Issuers. The Trustee shall not be liable for any losses, costs or expenses arising directly or indirectly from the Trustee’s reliance upon and compliance with such Instructions notwithstanding such directions conflict or are inconsistent with a subsequent written instruction. The Issuers agree: (i) to assume all risks arising out of the use of Electronic Means to submit Instructions to the Trustee, including without limitation the risk of the Trustee acting on unauthorized Instructions, and the risk of interception and misuse by third parties; (ii) that they are fully informed of the protections and risks associated with the various methods of transmitting Instructions to the Trustee and that there may be more secure methods of transmitting Instructions than the method(s) selected by the Company or the Co-Issuer, as the case may be; (iii) that the security procedures (if any) to be followed in connection with their transmission of Instructions provide to them a commercially reasonable degree of protection in light of their particular needs and circumstances; and (iv) to notify the Trustee immediately upon learning of any compromise or unauthorized use of the security procedures. The Trustee may execute this Second Indenture Supplement and any other documents delivered pursuant hereto (including authentication of the

13

Notes) via Electronic Means. “Electronic Means” shall mean the following communications methods: S.W.I.F.T., e-mail, secure electronic transmission containing applicable authorization codes, passwords and/or authentication keys issued by the Trustee, or another method or system specified by the Trustee as available for use in connection with its services hereunder.

[Signature Pages Follow]

14

IN WITNESS WHEREOF, each of the parties hereto has caused this Second Indenture Supplement to be duly signed, all as of the day and year first above written.

[Signature Page to the Second Indenture Supplement]

[Signature Page to the Second Indenture Supplement]

[Signature Page to the Second Indenture Supplement]

EXHIBIT A

FORM OF NOTE

Unless this Security is presented by an authorized representative of The Depository Trust Company (55 Water Street, New York, New York) to the Issuers or their agent for registration of transfer, exchange or payment, and any Security issued upon registration of transfer of, or in exchange for, or in lieu of, this Security is registered in the name of Cede & Co. or such other name as requested by an authorized representative of The Depository Trust Company and any payment hereon is made to Cede & Co., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL since the registered owner hereof, Cede & Co., has an interest herein.

AON NORTH AMERICA, INC.

AON GLOBAL HOLDINGS PLC

$  % Senior Notes Due 20

with full and unconditional guarantees

as to payment of principal and interest by

Aon plc, Aon Corporation and Aon Global Limited

No.

$

CUSIP No.

AON NORTH AMERICA, INC.

AON GLOBAL HOLDINGS PLC

Aon North America, Inc., a Delaware corporation (herein called the “Company,” which term includes any successor Person under the Indenture hereinafter referred to) and Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales (herein called the “Co-Issuer,” which term includes any successor Person under the Indenture hereinafter referred to, and, together with the Company, the “Issuers”), for value received, hereby jointly and severally promise to pay to Cede & Co., as nominee for The Depository Trust Company, or registered assigns, the principal sum of  ($  ) on  , 20 and, subject to Section 16.05 of said Indenture, to pay interest thereon from September 17, 2026 or from the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on each March 17 and September 17, commencing on March 17, 2027 (each, an “Interest Payment Date”), at the rate of % per annum, until the principal hereof is paid or made available for payment. The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more predecessor Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be March 2 or September 2 (whether or not a Business Day), as the case may be, immediately preceding such Interest Payment Date. Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more predecessor Securities) is registered at the close of business on a

A-1

subsequent record date for the payment of such defaulted interest established by the Issuers, notice whereof shall be given to Holders of Securities of this series not less than 15 days prior to such subsequent record date, such record date to be not less than 5 days preceding the date of payment of such defaulted interest, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Securities of this series may be listed, and upon such notice as may be required by such exchange, all as more fully provided in said Indenture.

Payment of the principal of and premium, if any, and interest on this Security will be made at the office or agency of the Company maintained for that purpose in the City of Chicago or the Borough of Manhattan, The City of New York, in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts; provided, however, that at the option of the Company or the Co-Issuer, payment of interest may be made by wire transfer, other electronic means or mailing checks to the address of the Holder entitled thereto as such address shall appear in the Security Register.

The Securities of this series are subject to redemption at the option of the Issuers prior to the stated maturity as described in the Indenture and on the reverse hereof.

Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place.

Unless the certificate of authentication hereon has been executed by the Trustee referred to herein by manual, facsimile or electronic signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.

NOTICE TO HOLDER

THE HOLDER OF THIS SECURITY IS HEREBY NOTIFIED, AND BY ITS ACCEPTANCE HEREOF ACKNOWLEDGES, THAT (1) THE ISSUERS AND A GUARANTOR, IN RESPECT OF ITS GUARANTEE, SHALL WITHHOLD OR DEDUCT FOR OR ON ACCOUNT OF ANY PRESENT OR FUTURE INCOME, STAMP OR OTHER TAX, DUTY, LEVY, IMPOST, ASSESSMENT OR OTHER GOVERNMENTAL CHARGE OF ANY NATURE WHATSOEVER IMPOSED OR LEVIED BY OR ON BEHALF OF THE GOVERNMENT OF THE UNITED STATES OR BY ANY AUTHORITY OR AGENCY THEREIN OR THEREOF HAVING THE POWER TO TAX (COLLECTIVELY, “UNITED STATES TAXES”) AS REQUIRED BY LAW OF THE UNITED STATES AND (2) IF THE COMPANY, THE CO-ISSUER OR A GUARANTOR (OR A WITHHOLDING AGENT FOR THE COMPANY, THE CO-ISSUER OR SUCH GUARANTOR) IS SO REQUIRED TO WITHHOLD OR DEDUCT ANY AMOUNT FOR OR ON ACCOUNT OF UNITED STATES TAXES FROM ANY PAYMENT, NO ADDITIONAL AMOUNTS SHALL BE PAID TO A HOLDER OR BENEFICIAL OWNER FOR OR WITH RESPECT TO THE AMOUNT SO WITHHELD OR DEDUCTED.

A-2

IN WITNESS WHEREOF, the Company and the Co-Issuer have caused this instrument to be duly executed.

Dated: September 17, 2026

[Seal]

Attest:

[Seal]

Attest:

[Co-Issuers’ Signature Page to the Global Note]

This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture.

Dated: September 17, 2026

[Trustee Signature Page to the Global Note]

This Security is one of a duly authorized series of securities of the Company and the Co-Issuer entitled “   % Senior Notes Due 20  ” (herein called the “Securities”) issued and to be issued under the Indenture, dated March 1, 2024, as supplemented by the Second Indenture Supplement, dated September 17, 2026, among the Issuers, the Guarantors and The Bank of New York Mellon Trust Company, N.A., as trustee (herein called the “Trustee,” which term includes any successor trustee under the Indenture, as defined below) (together, the “Indenture”), to which Indenture and all indentures supplemental thereto reference is hereby made for a statement of the respective rights, limitations of rights, duties and immunities thereunder of the Issuers, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and are to be, authenticated and delivered. The Securities of this series will initially be issued in the aggregate principal amount of $  . The Issuers may, from time to time, without the written consent of or notice to Holders of the Securities of this series, create and issue under the Indenture additional securities having the same terms and conditions as the Securities of this series (other than the issue date, the issue price and, to the extent applicable, the first date from which interest on such additional securities shall accrue and the first interest payment date for such additional securities) and such additional securities shall be consolidated with and form a single series with the Securities of this series.

Prior to   , 20 (   months prior to the Securities’ Stated Maturity) (the “Par Call Date”), the Issuers may redeem the Securities at their option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of the principal amount and rounded to three decimal places) equal to the greater of (i) (a) the sum of the present values of the remaining scheduled payments of principal and interest on the Securities being redeemed discounted to the redemption date (assuming the Securities being redeemed matured on the applicable Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate, plus  basis points ( %), less (b) interest accrued to the date of redemption, and (ii) 100% of the principal amount of the Securities being redeemed; and plus, in either case, accrued and unpaid interest on the principal amount of the Securities being redeemed to the redemption date.

On or after the Par Call Date, the Issuers may redeem the Securities, in whole or in part, at any time and from time to time, at a redemption price equal to 100% of the principal amount of the Securities being redeemed plus accrued and unpaid interest thereon to the redemption date.

“Treasury Rate” means, with respect to any redemption date, the yield determined by the Issuers in accordance with the following two paragraphs:

The Treasury Rate shall be determined by the Issuers after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third business day preceding the redemption date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as “Selected Interest Rates (Daily)—H.15” (or any successor designation or publication) (“H.15”) under the caption “U.S. government securities–Treasury constant maturities–Nominal” (or any successor caption or heading). In determining the Treasury Rate, the Issuers shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the Par Call Date (the “Remaining

Life”); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the redemption date.

If, on the third business day preceding the redemption date, H.15 is no longer published, the Issuers shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second business day preceding such redemption date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, the Issuers shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Issuers shall select from among these two or more United States Treasury securities the United States Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places. The Trustee shall have no responsibility to calculate, or to verify the Issuers’ calculation, of any redemption price.

In the event that the USI Acquisition (as defined below) is not consummated on or before the earliest of (i) the later of (x) June 1, 2027 and (y) such later date to which the outside date under the Merger Agreement (as defined below) as in effect on the issue date may be extended in accordance with the terms thereof, (ii) the valid termination of the Merger Agreement (other than in connection with the consummation of the USI Acquisition) and (iii) the Issuers’ determination based on their reasonable judgment (in which case the Issuers will notify the Trustee in writing thereof) that the USI Acquisition will not be consummated (any event described in clause (i), (ii) or (iii), a “Special Mandatory Redemption Event”), the Issuers will be required to redeem all of the outstanding USI Acquisition Notes of each series at a redemption price equal to 101% of the aggregate principal amount of such USI Acquisition Notes, plus accrued and unpaid interest, if any, to, but excluding, the redemption date (the “Special Mandatory Redemption Price”, and such redemption, a “Special Mandatory Redemption”). Upon the occurrence of a Special Mandatory Redemption Event, the Issuers will cause a notice of Special Mandatory Redemption to be transmitted to the Trustee and each holder of the USI Acquisition Notes at its registered address (or electronically delivered or otherwise transmitted in accordance with the depositary’s procedures) promptly, but in any event not later than five Business Days after the occurrence of such Special Mandatory Redemption Event, and will redeem the USI Acquisition Notes on the date specified in such notice (the date so specified, the “Special Mandatory Redemption Date”).

The Special Mandatory Redemption Date will be a date selected by the Issuers and set forth in the notice of Special Mandatory Redemption and will be no later than 30 days following the occurrence of the applicable Special Mandatory Redemption Event, but no earlier than the fifth Business Day following the day the notice of Special Mandatory Redemption is transmitted to holders of the USI Acquisition Notes. In no event shall the Trustee be responsible for monitoring the status of the USI Acquisition. If funds sufficient to pay the Special Mandatory Redemption Price of the USI Acquisition Notes on the Special Mandatory Redemption Date are deposited with the Trustee or a paying agent on or before such Special Mandatory Redemption Date, on and after such Special Mandatory Redemption Date, the USI Acquisition Notes will cease to bear interest.

“Merger Agreement” means the agreement and plan of merger, dated as of August 30, 2026, by and among Aon plc, the Company, Merger Sub, USI, and Uno Aggregator II L.P., a Delaware limited partnership.

“Merger Sub” means Cortlandt Acquisition Corp., a Delaware corporation and an indirect, wholly owned subsidiary of Aon plc.

“USI” means USI Advantage Corp., a Delaware corporation.

“USI Acquisition” means the acquisition by the Company of the issued and outstanding equity interests of USI pursuant to the Merger Agreement.¹

The Issuers’ actions and determinations in determining the redemption price shall be conclusive and binding for all purposes, absent manifest error. The Trustee shall have no responsibility to calculate, or to verify the Issuers’ calculation, of any redemption price.

Notice of any optional redemption will be mailed or electronically delivered (or otherwise transmitted in accordance with the depositary’s procedures) at least 10 days but not more than 90 days before the redemption date to each Holder of Securities to be redeemed. In the case of a partial redemption, selection of Securities in certificated form for redemption will be made by lot. Unless the Issuers default in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the Securities or portions thereof called for redemption. In the case of a partial redemption, selection of the Securities for redemption will be made pro rata, by lot or by such other method as the Trustee in its sole discretion deems appropriate and fair. For so long as the Securities are held by The Depository Trust Company (or another depositary), the redemption of the Notes shall be done in accordance with the policies and procedures of the depositary. Such notice of redemption may, at the Issuers’ discretion, be conditional, subject to one or more conditions precedent.

Notwithstanding the foregoing, installments of interest on Securities being redeemed that are due and payable on Interest Payment Dates falling on or prior to a redemption date will be payable on the Interest Payment Date to the registered Holders as of the close of business on the Regular Record Date according to the Securities and the Indenture.

All payments made by a Guarantor with respect to its Guarantee shall be made free and clear of and without withholding or deduction for or on account of any present or future income, stamp or other tax, duty, levy, impost, assessment or other governmental charge of any nature whatsoever imposed or levied by or on behalf of the government of the United Kingdom or Ireland, as applicable, or, in each case, by any authority or agency therein or thereof having the power to tax (collectively, “Taxes”), unless such Guarantor is required to withhold or deduct Taxes by law.

If an Event of Default with respect to the Securities of this series shall occur and be continuing, the principal amount of and accrued and unpaid interest, if any, on the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture.

The Indenture contains provisions for defeasance at any time of the entire indebtedness of this Security or certain restrictive covenants and Events of Default with respect to this Security, in each case upon compliance with certain conditions set forth therein.

The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Issuers and the rights of the Holders of the Securities of each series to be affected under the Indenture at any time by the Issuers and the Trustee with the consent of the Holders of a majority in principal amount of the Securities at the time Outstanding of each series to be affected. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities of each series at the time Outstanding, on behalf of the Holders of all Securities of such series, to waive compliance by the Issuers with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security.

No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Company and the Co-Issuer, which is joint and several, absolute and unconditional, to pay the principal of and any premium and interest on this Security at the times, place and rate, and in the coin or currency, herein prescribed.

As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registerable in the Security Register, upon surrender of this Security for registration of transfer at the office or agency of the Company or the Co-Issuer in any place where the principal of and any premium and interest on this Security are payable, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company or the Co-Issuer and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount will be issued to the designated transferee or transferees.

The Securities of this series are issuable only in registered form without coupons in denominations of $2,000 and integral multiples of $1,000. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of this series and of like tenor of a different authorized denomination, as requested by the Holder surrendering the same. No service charge shall be made for any such registration of transfer or exchange, but the Issuers may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith.

Prior to due presentment of this Security for registration of transfer, the Company, the Co-Issuer, the Trustee and any agent of the Company, the Co-Issuer or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, whether or not this Security be overdue, and none of the Company, the Co-Issuer, the Trustee or any such agent shall be affected by notice to the contrary.

Interest on this Security shall be computed on the basis of a 360-day year consisting of twelve 30-day months. Except as described below for the first Interest Payment Date, on each Interest Payment Date, the Issuers will pay interest on the Notes for the period commencing on (and including) the immediately preceding Interest Payment Date and ending on (and including) the day immediately preceding that Interest Payment Date. On the first Interest Payment Date, the Issuers will pay interest for the period beginning on (and including) the issue date to (but excluding) the first Interest Payment Date. If any Interest Payment Date falls on a day that is not a Business Day, the related interest payment shall be postponed to the next day that is a Business Day, and no interest on such payment shall accrue for the period from and after such Interest Payment Date. If the Stated Maturity or date of earlier redemption falls on a day that is not a Business Day, payment of principal and interest on such Notes will be made on the next succeeding day that is a Business Day, and no interest will accrue for the period from and after such Stated Maturity or date of earlier redemption. “Business Day” means any day, other than Saturday or Sunday, that is neither a legal holiday nor a day on which banking institutions are authorized or required by law, regulation or executive order to close in the City of New York.

All terms used but not defined in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture.

This Security shall be governed by and construed in accordance with the laws of the State of New York without giving effect to the conflict of laws provisions thereof.

ASSIGNMENT

I or we assign and transfer this Security to:

(Insert assignee’s social security or tax I.D. number)

(Print or type name, address and zip code of assignee)

and irrevocably appoint:

as agent to transfer this Security on the books of the Issuers. The agent may substitute another to act for him.

Signature Guarantee:                    

Signatures must be guaranteed by an “eligible guarantor institution” meeting the requirements of the Security Registrar, which requirements include membership or participation in the Security Transfer Agent Medallion Program (“STAMP”) or such other “signature guarantee program” as may be determined by the Security Registrar in addition to, or in substitution for, STAMP, all in accordance with the Securities Exchange Act of 1934, as amended.

NOTATION OF GUARANTEE

For value received, the undersigned Guarantor (which term includes any successor Person under the Indenture), subject to the provisions in the Indenture and the terms of the Securities of this series, has fully, unconditionally and irrevocably guaranteed to and for the benefit of each Holder and the Trustee the due and prompt payment in full of all amounts which may at any time be or become from time to time due and payable by the Issuers under the Indenture or otherwise with respect to the Securities of this series registered in such Holder’s name, at their stated due dates or when otherwise due in accordance with the terms thereof. The obligations of the Guarantor to the Holders of Securities and to the Trustee pursuant to the Guarantee under the Indenture are expressly set forth in Article Fifteen of the Indenture and reference is hereby made to the Indenture for the precise terms of the Guarantee. Each Holder of a Security, by accepting the same, (a) agrees to and shall be bound by such provisions and (b) appoints the Trustee attorney-in-fact of such Holder for the purpose of such provisions.

[Signature Page to the Notation of Guarantee]

NOTATION OF GUARANTEE

For value received, the undersigned Guarantor (which term includes any successor Person under the Indenture), subject to the provisions in the Indenture and the terms of the Securities of this series, has fully, unconditionally and irrevocably guaranteed to and for the benefit of each Holder and the Trustee the due and prompt payment in full of all amounts which may at any time be or become from time to time due and payable by the Issuers under the Indenture or otherwise with respect to the Securities of this series registered in such Holder’s name, at their stated due dates or when otherwise due in accordance with the terms thereof. The obligations of the Guarantor to the Holders of Securities and to the Trustee pursuant to the Guarantee under the Indenture are expressly set forth in Article Fifteen of the Indenture and reference is hereby made to the Indenture for the precise terms of the Guarantee. Each Holder of a Security, by accepting the same, (a) agrees to and shall be bound by such provisions and (b) appoints the Trustee attorney-in-fact of such Holder for the purpose of such provisions.

[Signature Page to the Notation of Guarantee]

NOTATION OF GUARANTEE

For value received, the undersigned Guarantor (which term includes any successor Person under the Indenture), subject to the provisions in the Indenture and the terms of the Securities of this series, has fully, unconditionally and irrevocably guaranteed to and for the benefit of each Holder and the Trustee the due and prompt payment in full of all amounts which may at any time be or become from time to time due and payable by the Issuers under the Indenture or otherwise with respect to the Securities of this series registered in such Holder’s name, at their stated due dates or when otherwise due in accordance with the terms thereof. The obligations of the Guarantor to the Holders of Securities and to the Trustee pursuant to the Guarantee under the Indenture are expressly set forth in Article Fifteen of the Indenture and reference is hereby made to the Indenture for the precise terms of the Guarantee. Each Holder of a Security, by accepting the same, (a) agrees to and shall be bound by such provisions and (b) appoints the Trustee attorney-in-fact of such Holder for the purpose of such provisions.

[Signature Page to the Notation of Guarantee]

Exhibit 5.1

SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP

Aon plc

15 George’s Quay

Dublin 2, Ireland

Ladies and Gentlemen:

We have acted as special United States counsel to Aon plc, a public limited company formed under the laws of Ireland (the “Company”), in connection with the public offering of $2,000,000,000 aggregate principal amount of the Issuers’ (as defined below) 5.350% Senior Notes due 2029 (the “2029 Notes”), $3,000,000,000 aggregate principal amount of the Issuers’ 5.625% Senior Notes due 2031 (the “2031 Notes”), $2,000,000,000 aggregate principal amount of the Issuers’ 5.800% Senior Notes due 2033 (the “2033 Notes”), $2,750,000,000 aggregate principal amount of the Issuers’ 5.950% Senior Notes due 2036 (the “2036 Notes”), $1,000,000,000 aggregate principal amount of the Issuers’ 6.100% Senior Notes due 2038 (the “2038 Notes”), $750,000,000 aggregate principal amount of the Issuers’ 6.450% Senior Notes due 2046 (the “2046 Notes”) and $2,000,000,000 aggregate principal amount of the Issuers’ 6.450% Senior Notes due 2056 (the “2056 Notes” and, together with the 2029 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes, the 2038 Notes and the 2046 Notes, the “Notes”), in each case to be issued under the Indenture, dated as of March 1, 2024 (the “Base Indenture”), among Aon North America, Inc., a Delaware corporation (“ANA”), Aon Global Holdings plc, a public

limited company formed under the laws of England and Wales (“AGH” and, collectively with ANA, the “Issuers” and each, an “Issuer”), the Guarantors (as defined below) and The Bank of New York Mellon Trust Company, N.A., as trustee (in such capacity, the “Trustee”), as supplemented by the second indenture supplement dated as of September 17, 2026 among the Issuers, the Guarantors and the Trustee (the “Second Indenture Supplement,” and together with the Base Indenture, the “Indenture”). The Indenture provides that the Notes are to be guaranteed by the Company, Aon Corporation, a Delaware corporation (“Aon Corporation”), and Aon Global Limited, a private limited company incorporated under the laws of England and Wales (“AGL” and, together with the Company and Aon Corporation, the “Guarantors”). The Notes and the Guarantees (as defined below) are collectively referred to herein as the “Securities.”

This opinion letter is being furnished in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act of 1933 (the “Securities Act”).

In rendering the opinions stated herein, we have examined and relied upon the following:

(a)  the registration statement on Form S-3 (File Nos. 333-297255, 333-297255-01, 333-297255-02, 333-297255-03, and 333-297255-04) of the Opinion Parties (as defined below) relating to debt securities and other securities of the Opinion Parties filed on July 2, 2026 with the Securities and Exchange Commission (the “Commission”) under the Securities Act allowing for delayed offerings pursuant to Rule 415 of the General Rules and Regulations under the Securities Act (the “Rules and Regulations”), including the information deemed to be a part of the registration statement pursuant to Rule 430B of the Rules and Regulations (such registration statement being hereinafter referred to as the “Registration Statement”);

(b)  the prospectus, dated July 2, 2026 (the “Base Prospectus”), which forms a part of and is included in the Registration Statement;

(c)  the preliminary prospectus supplement, dated September 11, 2026 (together with the Base Prospectus, the “Preliminary Prospectus”), relating to the offering of the Securities, in the form filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations;

(d)  the prospectus supplement, dated September 14, 2026 (together with the Base Prospectus, the “Prospectus”), relating to the offering of the Securities, in the form filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations;

(e)  an executed copy of the Underwriting Agreement, dated September 14, 2026 (the “Underwriting Agreement”), among the Opinion Parties and Citigroup Global Markets Inc., BofA Securities, Inc., Morgan Stanley & Co. LLC, Wells Fargo Securities, LLC and HSBC Securities (USA) Inc. as representatives of the several Underwriters named therein (the “Underwriters”), relating to the sale by the Issuers to the Underwriters of the Securities;

(f)  the global certificates evidencing the Notes, executed by the Issuers and registered in the name of Cede & Co. (the “Note Certificates”), delivered by the Issuers to the Trustee for authentication and delivery;

(g)  an executed copy of the Base Indenture, including Section 15.01 of the Base Indenture and Section 2.02 of the Second Indenture Supplement, containing the guaranty obligations of the Guarantors (the “Guarantees”);

(h)  an executed copy of the Second Indenture Supplement;

(i)  executed copies of certificates for each Delaware Opinion Party (as defined below) of Colby Alexis, Secretary of each of the Delaware Opinion Parties, dated the date hereof (together, the “Secretary’s Certificates”);

(j)  a copy of each Delaware Opinion Party’s Certificate of Incorporation, as amended, and Certificate of Amendment, as applicable, certified by the Secretary of State of the State of Delaware as of September 17, 2026, and certified pursuant to the Secretary’s Certificates as being in effect on the date of the resolutions referred to below and as of the date hereof;

(k)  a copy of each Delaware Opinion Party’s bylaws, certified pursuant to the applicable Secretary’s Certificates as being in effect on the date of the resolutions referred to below and as of the date hereof; and

(l)  a copy of certain resolutions of the Board of Directors of each Opinion Party, adopted on August 30, 2026 and September 11, 2026, certified pursuant to the Secretary’s Certificates.

We have also examined originals or copies, certified or otherwise identified to our satisfaction, of such records of the Opinion Parties and such agreements, certificates and receipts of public officials, certificates of officers or other representatives of the Opinion Parties and others, and such other documents as we have deemed necessary or appropriate as a basis for the opinions stated below.

In our examination, we have assumed the genuineness of all signatures, including electronic signatures, the legal capacity and competency of all natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as facsimile, electronic, certified or photocopied copies, and the authenticity of the originals of such copies. As to any facts relevant to the opinions stated herein that we did not independently establish or verify, we have relied upon statements and representations of officers and other representatives of the Opinion Parties and others and of public officials, including the facts and conclusions set forth in the Secretary’s Certificates and the factual representations and warranties contained in the Underwriting Agreement.

We do not express any opinion with respect to the laws of any jurisdiction other than (i) the laws of the State of New York and (ii) the General Corporation Law of the State of Delaware (the “DGCL”) (all of the foregoing being referred to as “Opined-on Law”).

As used herein, (i) “Opinion Parties” means, collectively, the Issuers and the Guarantors (each, an “Opinion Party”), (ii) “Delaware Opinion Parties” means, collectively, ANA and Aon Corporation (each, a “Delaware Opinion Party”) and (iii) “Transaction Documents” means the Underwriting Agreement, the Indenture and the Note Certificates.

Based upon the foregoing and subject to the qualifications and assumptions stated herein, we are of the opinion that:

1.  The Note Certificates have been duly authorized by all requisite corporate action on the part of ANA and duly executed by ANA under the DGCL, and when duly authenticated by the Trustee and issued and delivered by the Issuers against payment therefor in accordance with the terms of the Underwriting Agreement and the Indenture, the Note Certificates will constitute valid and binding obligations of the Issuers, enforceable against the Issuers in accordance with their terms under the laws of the State of New York.

2.  The Guarantee of Aon Corporation has been duly authorized by all requisite corporate action on the part of Aon Corporation under the DGCL and, when the Note Certificates are duly authenticated by the Trustee and issued and delivered by the Issuers against payment therefor in accordance with the terms of the Underwriting Agreement and the Indenture, the Guarantees will constitute valid and binding obligations of the Guarantors, enforceable against the Guarantors in accordance with their terms under the laws of the State of New York.

The opinions stated herein are subject to the following assumptions and qualifications:

(a)  we do not express any opinion with respect to the effect on the opinions stated herein of any bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer, preference and other similar laws or governmental orders affecting creditors’ rights generally, and the opinions stated herein are limited by such laws and governmental orders and by general principles of equity (regardless of whether enforcement is sought in equity or at law);

(b)  we do not express any opinion with respect to any law, rule, regulation or order that is applicable to any party to any of the Transaction Documents or the transactions contemplated thereby solely because such law, rule, regulation or order is part of a regulatory regime applicable to any such party or any of its affiliates as a result of the specific assets or business operations of such party or such affiliates;

(c)  except to the extent expressly stated in the opinions contained herein, we have assumed that each of the Transaction Documents constitutes the valid and binding obligation of each party to such Transaction Document, enforceable against such party in accordance with its terms;

(d)  we do not express any opinion with respect to the enforceability of any provision contained in any Transaction Document relating to any indemnification, contribution, non-reliance, exculpation, release, limitation or exclusion of remedies, waiver, or other provisions having similar effect that may be contrary to public policy or violative of federal or state securities laws, rules, regulations or orders, or to the extent any such provision purports to waive or alter, or has the effect of waiving or altering, any statute of limitations;

(e)  we do not express any opinion as to whether the execution or delivery of any Transaction Document by any Opinion Party, or the performance by any Opinion Party of its obligations under any Transaction Document to which such Opinion Party is a party, will constitute a violation of, or a default under, any covenant, restriction or provision with respect to financial ratios or tests or any aspect of the financial condition or results of operations of any Opinion Party or any of its subsidiaries;

(f)  the opinions stated herein are limited to the agreements and documents specifically identified in the opinions contained herein (the “Specified Documents”) without regard to any agreement or other document referenced in any Specified Document (including agreements or other documents incorporated by reference or attached or annexed thereto) and without regard to any other agreement or document relating to any Specified Document that is not a Transaction Document;

(g)  this opinion letter shall be interpreted in accordance with customary practice of United States lawyers who regularly give opinions in transactions of this type;

(h)  we have assumed that subsequent to the effectiveness of the Base Indenture and immediately prior to the effectiveness of the Second Indenture Supplement, the Base Indenture has not been amended, restated, supplemented or otherwise modified in any way that affects or relates to the Notes Certificates other than by the applicable Transaction Documents relating to such Securities;

(i)  to the extent that any opinion relates to the enforceability of the choice of New York law and choice of New York forum provisions contained in any Transaction Document, the opinions stated herein are subject to the qualification that such enforceability may be subject to, in each case, (i) the exceptions and limitations in New York General Obligations Law Sections 5-1401 and 5-1402 and (ii) principles of comity and constitutionality;

(j)  we do not express any opinion with respect to the enforceability of Section 15.01 of the Base Indenture or Section 2.02 of the Second Indenture Supplement, as applicable, to the extent that such section provides that the obligations of the Guarantors of their Guarantees are absolute and unconditional irrespective of the enforceability or genuineness of the Indenture or the effect thereof on the opinions herein stated;

(k)  we do not express any opinion with respect to the enforceability of the provisions contained in Section 15.04 of the Base Indenture or Section 2.02 of the Second Indenture Supplement, as applicable, to the extent that such provisions limit the obligation of the Guarantors of their Guarantees under the Indenture or any right of contribution of any party with respect to the Guarantees;

(l)  we call to your attention that irrespective of the agreement of the parties to any Transaction Document, a court may decline to hear a case on grounds of forum non conveniens or other doctrine limiting the availability of such court as a forum for resolution of disputes; in addition, we call to your attention that we do not express any opinion with respect to the subject matter jurisdiction of the federal courts of the United States of America in any action arising out of or relating to any Transaction Document;

(m)  we have assumed that Corporation Service Company has accepted appointment as agent to receive service of process and call to your attention that we do not express any opinion if and to the extent such agent shall resign such appointment. Further, we do not express any opinion with respect to the irrevocability of the designation of such agent to receive service of process;

(n)   we call to your attention that the opinions stated herein are subject to possible judicial action giving effect to governmental actions or laws of jurisdictions other than those with respect to which we express our opinion; and

(o)  we do not express any opinion with respect to the enforceability of any provision contained in any Transaction Document providing for indemnity by any party thereto against any loss in obtaining the currency due to such party under any Transaction Document from a court judgment in another currency.

In addition, in rendering the foregoing opinions we have also assumed that, at all applicable times:

(a)  The Company, AGH and AGL (i) was duly incorporated and was validly existing and in good standing, (ii) had requisite legal status and legal capacity under the laws of the jurisdiction of its organization and (iii) has complied and will comply with all aspects of the laws of the jurisdiction of its organization in connection with the transactions contemplated by, and the performance of its obligations under, the Transaction Documents to which the Non-Opinion Party Guarantor is a party;

(b)  The Company, AGH and AGL had the corporate power and authority to execute, deliver and perform all its obligations under each of the Transaction Documents;

(c)  each of the Transaction Documents to which each of the Company, AGH and AGL is a party had been duly authorized, executed and delivered by all requisite corporate action on the part of the Company, AGH and AGL, respectively;

(d)  neither the execution and delivery by each Opinion Party of the Transaction Documents to which each Opinion Party is a party nor the performance by each Opinion Party of its obligations thereunder, including the issuance and sale of the Securities: (i) conflicted or will conflict with the articles or certificates of incorporation, certificate of formation, as applicable, or any other comparable organizational document of each Opinion Party, (ii) constituted or will constitute a violation of, or a default under, any lease, indenture, agreement or other instrument to which each Opinion Party or its property is subject (except that we do not make the assumption set forth in this clause (ii) with respect to those agreements or instruments expressed to be governed by the laws of the State of New York which are listed in Part II of the Registration Statement or the Company’s Annual Report on Form 10-K for the year ended December 31, 2025), (iii) contravened or will contravene any order or decree of any governmental authority to which each Opinion Party or its property is subject, or (iv) violated or will violate any law, rule or regulation to which each Opinion Party or its property is subject (except that we do not make the assumption set forth in this clause (iv) with respect to the Opined-on Law); and

(e)  neither the execution and delivery by the Issuers or any Guarantor of the Transaction Documents to which the Issuers or such Guarantor is a party nor the performance by the Issuers and such Guarantor of its obligations thereunder, including the issuance and sale of the Securities, required or will require the consent, approval, licensing or authorization of, or any filing, recording or registration with, any governmental authority under any law, rule or regulation of any jurisdiction.

We hereby consent to the reference to our firm under the heading “Legal Matters” in the Preliminary Prospectus and the Prospectus. In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations. We also hereby consent to the filing of this opinion letter with the Commission as an exhibit to the Company’s Current Report on Form 8-K being filed on the date hereof and incorporated by reference into the Registration Statement. This opinion letter is expressed as of the date hereof unless otherwise expressly stated, and we disclaim any undertaking to advise you of any subsequent changes in the facts stated or assumed herein or of any subsequent changes in applicable laws.

Exhibit 5.2

SKADDEN, ARPS, SLATE, MEAGHER & FLOM (UK) LLP

Aon plc

15 George’s Quay

Dublin 2

Ireland

D02 VR98

Ladies and Gentlemen,

Aon North America, Inc. and Aon Global Holdings plc – Prospectus Supplement – Exhibit 5.2

SKADDEN, ARPS, SLATE, MEAGHER & FLOM (UK) LLP, A LIMITED LIABILITY PARTNERSHIP REGISTERED UNDER THE LAWS OF THE STATE OF DELAWARE, IS AUTHORISED AND REGULATED BY THE SOLICITORS REGULATION AUTHORITY UNDER REFERENCE NUMBER 80014.

A LIST OF THE FIRM’S PARTNERS IS OPEN TO INSPECTION AT THE ABOVE ADDRESS.

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(together, the “Documents”) and such other documents, and made such searches and considered such facts, as we consider appropriate for the purpose of this opinion. The documents listed at paragraphs (c) and (g) above are referred to in this opinion as the “Transaction Documents”. We express no opinion as to any agreement, instrument or document other than the Transaction Documents and then only as expressly specified in this opinion.

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Assumptions

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Opinion

Qualifications

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as notice of these matters may not be filed with the Registrar of Companies immediately and, when filed, may not be entered on the public file of the relevant Company immediately. Those searches and enquiries are not capable of revealing, prior to the making of the relevant order, whether or not a winding up petition or a petition for an administration order has been presented nor would they reveal if insolvency proceedings have begun elsewhere;

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Exhibit 5.3

Dear Addressee

Aon North America, Inc. and Aon Global Holdings plc Senior Notes Offering

We act as legal advisers to Aon plc, a public limited company incorporated under the laws of Ireland with company number 604607 (the “Company”), which has asked us to give this Opinion as to certain matters of Irish law in connection with the filing by the Company, Aon North America, Inc., a Delaware corporation (“ANA”), Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales (“AGH”, and together with ANA, the “Issuers”), Aon Corporation, a Delaware corporation and Aon Global Limited, a private limited company incorporated under the laws of England and Wales (“AGL”, and together with the Company and Aon Corporation, the “Guarantors”), on 14 September 2026, of a prospectus supplement (the “Prospectus Supplement”) to the base prospectus dated 2 July 2026 (the “Base Prospectus”) included in the shelf registration statement on Form S-3 filed by the Issuers and the Guarantors on 2 July 2026 (Registration Nos. 333-29255, 333-297255-01, 333-297255-02, 333-297255-03 and 333-297255-04) (the “Registration Statement”) with the U.S. Securities and Exchange Commission (the “Commission”) under the U.S. Securities Act of 1933, as amended (the “Securities Act”).

The Prospectus Supplement relates to the offer and sale by the Issuers of US$2,000,000,000 aggregate principal amount of 5.350% Senior Notes due 2029 (the “2029 Notes”), US$3,000,000,000 aggregate principal amount of 5.625% Senior Notes due 2031 (the “2031 Notes”), US$2,000,000,000 aggregate principal amount of 5.800% Senior Notes due 2033 (the “2033 Notes”), US$2,750,000,000 aggregate principal amount of 5.950% Senior Notes due 2036 (the “2036 Notes”), US$1,000,000,000 aggregate principal amount of 6,100% Senior Notes due 2038 (the “2038 Notes”), US$750,000,000 aggregate principal amount of 6.450% Senior Notes due 2046 (the “2046 Notes”) and US$2,000,000,000 aggregate principal amount of 6.450% Senior Notes due 2056 (the “2056 Notes”, and together with the 2029 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes, the 2038 Notes and the 2046 Notes, the “Notes”).

The Notes are to be issued under the New York law governed base indenture dated 1 March 2024, filed with the Commission on 1 March 2024 as Exhibit 4.1 to the Company’s Current Report on Form 8-K, made among the Issuers, the Guarantors and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”) (the “Base Indenture”), as supplemented by the second indenture supplement dated the date hereof made among the Issuers, the Guarantors and the Trustee (the “Second Indenture Supplement”, and together with the Base Indenture, the “Indenture”). The Indenture provides that the Notes are to be guaranteed by the Guarantors (such guarantee obligations, being the “Guarantees”).

The Notes are to be sold pursuant to a New York law governed underwriting agreement dated 14 September 2026 made among the Issuers, the Guarantors and Citigroup Global Markets Inc., BofA Securities, Inc., HSBC Securities (USA) Inc., Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC, as representatives of the several underwriters named therein (the “Underwriting Agreement”).

For the purpose of giving this Opinion, we have examined the documents and have conducted the searches listed in Schedule 1 (Documents and Searches) to this Opinion, together with such other materials as we have considered necessary or relevant as a basis for the opinions contained herein.

This Opinion is strictly limited to the matters expressly stated under Section 3 (Opinions), below, and is not to be read as extending, by implication or otherwise, to any other matter. In particular, this Opinion does not deal with any tax matter or the tax consequences of any matter referred to in this Opinion, in the documents or other materials examined by us for the purpose of giving this Opinion, or otherwise.

We express no opinion and make no representation or warranty as to any matter of fact. We have not investigated or verified any of the facts or assumptions, or the reasonableness of any assumptions, statements or opinions contained or represented by any person in the documents or other materials examined by us for the purposes of giving this Opinion, nor have we attempted to determine if any relevant facts have been omitted from such documents or materials.

This Opinion is given with respect to the laws of Ireland in effect on the date hereof and is based on legislation published and cases fully reported before that date and our knowledge of the facts relevant to the opinions contained herein. For the avoidance of doubt, Ireland does not include Northern Ireland (which is a separate jurisdiction), and references to the laws of Ireland do not include the laws in force in Northern Ireland.

We have made no investigations of, and we express no opinion on, the laws of any jurisdiction other than Ireland, or the effect thereof. In particular, we have made no investigations of any reference to non-Irish laws in any document or other materials examined by us or the meaning or effect thereof, and any phrases used in any non-Irish law governed document examined by us have been construed by us as having the meaning and effect they would have if such document was governed by Irish law. We have assumed, without enquiry, that there is nothing in the laws of any jurisdiction other than Ireland which would, or might, affect the opinions contained herein, and that, insofar as the laws of any jurisdiction other than Ireland are relevant, such laws have been, or will be, complied with.

This Opinion is expressed as of the date hereof and we assume no obligation to update the opinions contained herein.

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Based upon, and subject to, the foregoing and the assumptions, qualifications and limitations set out in Schedule 2 (Assumptions), Schedule 3 (Qualifications) and elsewhere in this Opinion, we are of the following opinions:

This Opinion is furnished to you and the persons entitled to rely upon it pursuant to the applicable provisions of the Securities Act strictly for use in connection with the Registration Statement and may not be relied upon by any other person without our prior written consent.

We hereby consent to the filing of this Opinion as Exhibit 5.3 to the Current Report on Form 8-K relating to the Notes, to be filed by the Company on the date hereof and to the references to Matheson LLP under the caption “Legal Matters” in the Prospectus Supplement forming part of the Registration Statement. In giving such consent, we do not admit that we are included in the category of persons whose consent is required under section 7 of the Securities Act, or the rules and regulations of the Commission promulgated thereunder.

This Opinion and the opinions contained herein are governed by, and shall be construed in accordance with, the laws of Ireland.

Yours faithfully

/s/ Matheson LLP

MATHESON LLP

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Schedule 1

Documents and Searches

For the purpose of giving this Opinion, we have examined the documents and have conducted the searches listed below.

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Schedule 2

Assumptions

The opinions contained herein are given on the basis of the assumptions set out in this Schedule.

All signatures (including, for the avoidance of doubt, electronic signatures), initials, seals and stamps contained in, or on, any document examined by us are genuine.

All documents provided to us as originals are authentic and complete and all documents provided to us as copies (including, without limitation, any document provided to us as a .pdf (or any other format) attachment to an email) are complete and conform to the originals of such documents, and the originals of such documents are authentic and complete with all requisite seals and stamps affixed.

The contents of the documents (including the Corporate Certificate) and any other materials examined by us for the purposes of this Opinion are true and accurate as to factual matters, but we have made no independent investigation regarding such factual matters.

All documents dated on, or prior to, the date hereof and on which we have expressed reliance have not been revoked or amended and remain accurate.

Each natural person who has executed any document examined by us for the purposes of this Opinion had the due personal legal capacity to do so.

Any electronic signature inserted on a document was inserted by the signatory in question and not by another person and where attested by a witness was inserted in the physical presence of the witness. Each party to any document which has been executed using electronic signatures has consented to the execution of that document by way of electronic signature.

The Indenture has been unconditionally delivered by the parties thereto (including the Company) and is not subject to any escrow or similar arrangement.

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There have been no amendments to the Constitutional Documents or the other attachments to the Corporate Certificate.

The resolutions documented in the Board Resolutions’ Extract were passed at a properly convened, constituted and quorate meeting of the board of directors of the Company, and such resolutions have not, since their date of adoption, been amended, superseded or rescinded and are in full force and effect. The Written Board Resolutions have not, since their date of adoption, been amended, superseded or rescinded, and are in full force and effect.

The Company has derived, or will derive, a commercial benefit from entering into the Indenture and any other document referred to in, or contemplated by, the Preliminary Prospectus and the Prospectus (including the Underwriting Agreement) and giving the Guarantees, in each case commensurate with the obligations undertaken by it thereunder.

In approving the entry into the Indenture and any other document referred to in, or contemplated by, the Indenture, the Preliminary Prospectus or the Prospectus (including the Underwriting Agreement) and giving the Guarantees, the directors of the Company have acted, or will act, in good faith in the interests of the Company for the benefit of its members as a whole and for its legitimate business purposes.

In approving the entry into the Indenture and any other document referred to in, or contemplated by, the Indenture, the Preliminary Prospectus and the Prospectus (including the Underwriting Agreement) and giving the Guarantees, each director of the Company has disclosed any interest which he or she may have in the relevant transactions in accordance with the provisions of the Companies Act 2014 of Ireland, as amended (the “Companies Act”) and the Company’s constitution.

No director or secretary of the Company is the subject of any declaration, order or deemed order for disqualification or restriction under the Companies Act, including Chapters 3 and 4 of Part 14 thereof, and no such person has received any notice under the Companies Act regarding a disqualification or restriction undertaking.

The Company together with any other entity whose obligations are guaranteed by it under the Indenture together comprise a “group” for the purposes of section 243 of the Companies Act, and any person that subsequently becomes an issuer or a guarantor under the Indenture will also be a member of such group.

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The Company will not, by virtue of entering into the Indenture and any other document referred to in, or contemplated by, the Indenture, Preliminary Prospectus and the Prospectus (including the Underwriting Agreement) and giving the Guarantees, give any financial assistance (as contemplated by sections 82 and 1043 of the Companies Act) for the purpose of the acquisition of any shares in the capital of the Company, save as permitted by, or pursuant to an exemption from the application of, the said sections 82 and 1043.

Each person expressed to be a party to the Indenture (other than the Company):

The information disclosed by the Searches was accurate and complete as of the date the Searches were made and has not been altered. The Searches did not fail to disclose any information which had been delivered for registration but which did not appear from the information available at the time the Searches were made or which ought to have been delivered for registration at that time but had not been so delivered. No additional matters would have been disclosed by additional searches being carried out since that time.

The Company was solvent immediately following the execution of the Second Indenture Supplement.

The Company will not be insolvent as a consequence of: (a) executing and delivering the Second Indenture Supplement, (b) giving the Guarantees and / or (c) doing any other act or thing referred to in, or contemplated by, the Indenture, the Preliminary Prospectus or the Prospectus(including the Underwriting Agreement).

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No receiver has been appointed in relation to the Company or any of its assets or undertaking.

The Company has not passed a voluntary winding-up resolution or a resolution to place the Company under court protection or to appoint a process adviser, and no petition has been presented to, or order made by, a court for the winding-up of the Company or to place the Company under court protection or for the appointment of a process adviser.

In approving the giving of the Guarantees, there was no intent by the Company to give a creditor a preference which could be deemed an unfair preference in accordance with section 604 of the Companies Act.

The obligations expressed to be assumed by each party to the Indenture constitute legal, valid, binding and enforceable obligations under all applicable laws and in all applicable jurisdictions (other than, in the case of the Company, the laws of Ireland and the jurisdiction of Ireland).

If any obligation of any of the parties under the Indenture or any other document referred to in, or contemplated by, the Indenture, the Preliminary Prospectus or the Prospectus (including the Underwriting Agreement) is to be performed in any jurisdiction other than Ireland, its performance will not be illegal or ineffective by virtue of the law of that jurisdiction.

There are no provisions of the laws or public policy of any jurisdiction outside Ireland which would be contravened by the execution or performance of the Indenture or any other document referred to in, or contemplated by, the Indenture, the Preliminary Prospectus or the Prospectus (including the Underwriting Agreement) or which would render their performance ineffective by virtue of the laws of that jurisdiction.

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Neither the Notes nor the Guarantees will be listed or traded on a stock exchange or other market in the European Economic Area.

The offering and sale of the Notes and the giving of the Guarantees and any transfers and payments to be made thereunder or in connection therewith are not, and will not be, affected or prohibited by any financial restrictions or sanctions imposed by the United Nations, the European Union or Ireland or which arise under any human rights, anti-terrorism, anti-corruption, anti-money laundering or exchange control laws and regulations of the European Union or Ireland, including, without limitation, any arising from orders made under the Financial Transfers Act 1992 of Ireland, the Criminal Justice (Terrorist Offences) Acts 2005 and 2015 of Ireland or the Criminal Justice (Money Laundering and Terrorist Financing) Acts 2010 to 2021 of Ireland.

There has been no bad faith, fraud, coercion, duress or undue influence on the part of any of the parties to any of the documents or other materials we have examined for the purpose of this Opinion (including the Company), or their respective directors, employees, agents and / or advisers.

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Schedule 3

Qualifications

The opinions contained herein are given subject to the qualifications set out in this Schedule.

There are some potential limitations to the effectiveness of the Searches. These include:

The expressions “legal”, “valid” and “binding” and any combination or variations thereof when used in Section 3 (Opinions), mean that the obligations expressed to be assumed under an agreement are of a type which the courts of Ireland will treat as valid, binding and enforceable. It does not mean that these obligations will necessarily be enforced in all circumstances in accordance with their terms. In particular, enforcement of obligations under an agreement may be:

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The Companies Act prohibits certain steps being taken, except with the leave of the High Court, against a company after the presentation of a petition for the appointment of an examiner. This prohibition continues for so long as the examiner remains appointed. An examiner may remain appointed for a maximum period of one hundred days during which time the examiner must complete a report to formulate proposals for a compromise or scheme of arrangement in relation to the company concerned. Following the submission of this report to the High Court, the High Court may extend the period of appointment by such further period as the High Court considers necessary to enable it to take a decision as to whether it confirms the proposals set forth by the examiner. Prohibited steps include steps taken to withhold performance of, terminate or accelerate any executory contract solely by reason of the making of a petition to appoint, or the appointment of, an examiner or because the company is unable to pay its debts, steps taken to enforce any security over the company’s property, the commencement or continuation of proceedings or execution or other legal process or the levying of distress against the company or its property and the appointment of a receiver.

Under the provisions of the Companies Act, an examiner can also be appointed on a petition to the Circuit Court, if certain criteria are met. It is not possible for anyone other than a party to the relevant proceedings or the solicitors on record for such parties to inspect the Circuit Court files to ascertain whether a petition for the appointment of an examiner has been made in the Circuit Court, and we have made no searches or enquiries in this regard in respect of the Company.

A contractual provision conferring or imposing a remedy or an obligation consequent upon default may not be enforceable if it were construed by an Irish court as being a penalty, particularly if it involved enforcing an additional pecuniary remedy (such as a default or overdue interest) referable to such default and which does not constitute a genuine and reasonable pre-estimate of the damage likely to be suffered as a result of the default in payment of the amount in question or the termination in question; further, recovery may be limited by laws requiring mitigation of loss suffered.

An Irish court may not give effect to an indemnity given by any party in an agreement or other document to the extent it is in respect of legal costs incurred by an unsuccessful litigant or to the extent that it is in respect of litigation costs which are not awarded by the court.

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In the event of any proceedings being brought in an Irish court in respect of a monetary obligation expressed to be payable in a currency other than euro an Irish court would have the power to give a judgment to pay a currency other than euro, it may decline to do so in its discretion and an Irish court might not enforce the benefit of currency conversion or indemnity clauses and, with respect to a bankruptcy, liquidation, insolvency, reorganisation or similar proceeding, the law of Ireland may require that all claims or debts are converted into euro at an exchange rate determined by the court as at a date related thereto, such as the date of commencement of a winding up.

A determination or calculation of any party to an agreement stated in that agreement to be conclusive may be held by the courts of Ireland not to be final, conclusive or binding.

The effect of terms, if any, in an agreement excusing a party from a liability or duty otherwise owed are limited by law.

Where a party is vested with a discretion or may determine a matter in his or its opinion, the laws of Ireland may require that such discretion is exercised reasonably or that such opinion is based upon reasonable grounds.

The courts of Ireland may interpret restrictively any provision purporting to allow the beneficiary of a guarantee or other suretyship to make a material amendment to the obligations to which the guarantee or suretyship relates without further reference to the guarantor or surety.

The enforceability of any provision as to severability may be determined by the courts of Ireland at its discretion.

No opinion is expressed on the irrevocability of any power of attorney.

An Irish court may not give effect to any provision of an agreement which: (a) provides for a matter to be determined by future agreement or negotiation, or (b) it considers to be devoid of any meaning, vague or uncertain.

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A right of set-off provided for in a contract or another document may not be enforceable in all circumstances.

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