Exhibit 99.1

UNDERWRITING AGREEMENT

February 23, 2024

Colliers International Group Inc.

1140 Bay Street
Suite 4000
Toronto, Ontario
M5S 2B4

Attention:     Christian Mayer, Chief Financial Officer

Dear Sir:

BMO Nesbitt Burns Inc. (“BMO Capital Markets”), as lead bookrunner, and J.P. Morgan Securities Canada Inc. (together with BMO Capital Markets, the “Joint Bookrunners”), and Mizuho Securities Canada Inc., National Bank Financial Inc., RBC Dominion Securities Inc., Scotia Capital Inc., Merrill Lynch Canada Inc., CIBC World Markets Inc., Goldman Sachs Canada Inc., Raymond James Ltd., TD Securities Inc., BTIG, LLC, Wells Fargo Securities Canada, Ltd., and Stifel Nicolaus Canada Inc. (together with the Joint Bookrunners, the “Underwriters” and each individually an “Underwriter”) hereby severally, and not jointly nor jointly and severally, agree to purchase from Colliers International Group Inc. (the “Corporation”) in the respective percentages set forth in Section 21, and the Corporation hereby agrees to issue and sell to the Underwriters, upon and subject to the terms hereof, an aggregate of 2,479,500 Subordinate Voting Shares (as defined herein) of the Corporation (the “Firm Shares”) on an underwritten “bought deal” basis at a price of US$121.00 per Firm Share (the “Offering Price”) for aggregate gross proceeds of US$300,019,500.00.

Upon and subject to the terms and conditions contained herein, the Corporation hereby grants to the Underwriters an option (the “Over-Allotment Option”) to purchase severally, and not jointly nor jointly and severally, in the respective percentages set forth in Section 21 hereof, up to an additional 371,925 Subordinate Voting Shares of the Corporation (the “Additional Shares”) at a price of US$121.00 per Additional Share for the purpose of covering the Underwriters’ over-allocation position and for market stabilization purposes. The Over-Allotment Option may be exercised in accordance with Section 15 hereof. The Firm Shares and the Additional Shares are collectively referred to herein as the “Offered Shares”.

The Underwriters understand that the Corporation has prepared and filed with each of the Canadian Securities Commissions (as defined herein) the Canadian Base Shelf Prospectus (as defined herein) in respect of subordinate voting shares, preference shares, debt securities, warrants, subscription receipts and units of the Corporation, omitting the Shelf Information (as defined herein) in accordance with the Shelf Procedures (as defined herein) and that the Corporation has received a Prospectus Receipt (as defined herein) for the Canadian Base Shelf Prospectus on February 20, 2024. The term “Canadian Base Shelf Prospectus” means the final short form base shelf prospectus dated February 20, 2024 at the time the Prospectus Receipt was issued with respect thereto in accordance with Canadian Securities Laws (as defined herein), including the Shelf Procedures (as defined herein) and the WKSI Blanket Orders (as defined herein), and includes all Documents Incorporated by Reference (as defined herein). The Corporation has also prepared and filed a preliminary prospectus supplement relating to the Offering (as defined herein), which excluded certain Shelf Information, with the Canadian Securities Commissions, in accordance with the Shelf Procedures (including the Documents Incorporated by Reference, the “Canadian Preliminary Prospectus Supplement”). The Canadian Preliminary Prospectus Supplement, together with the Canadian Base Shelf Prospectus, is hereinafter called the “Canadian Preliminary Prospectus”.

The Underwriters also understand that the Corporation has prepared and filed with the United States Securities and Exchange Commission (the “SEC”) pursuant to the Canada/U.S. Multijurisdictional Disclosure System adopted by the SEC (the “MJDS”), a registration statement on Form F-10 (File No. 333-277184) covering the public offering and sale of the securities qualified under Applicable Securities Laws (as defined herein) by the Canadian Base Shelf Prospectus, including the Offered Shares, under the United States Securities Act of 1933, as amended (the “U.S. Securities Act”), and the rules and regulations of the SEC thereunder (the Canadian Base Shelf Prospectus, together with any Documents Incorporated by Reference therein, any supplements or amendments thereto and with such deletions therefrom and additions or changes thereto as are permitted or required by Form F-10 and the applicable rules and regulations of the SEC, in the form included in such Form F-10, the “U.S. Base Prospectus” and such registration statement, including the prospectus contained therein at the time it becomes effective, as amended or supplemented, and the exhibits thereto and the Documents Incorporated by Reference therein, in the form in which it became effective, is herein called the “Registration Statement”). The Corporation has also prepared and filed with the SEC an appointment of agent for service of process upon the Corporation on Form F-X (the “Form F-X”) in conjunction with the filing of the Registration Statement. The Corporation has also prepared and filed with the SEC, in accordance with General Instruction II.L of Form F-10, the Canadian Preliminary Prospectus Supplement, with such deletions therefrom and additions or changes thereto, as are permitted or required by Form F-10 and the applicable rules and regulations of the SEC (the “U.S. Preliminary Prospectus Supplement”). The U.S. Preliminary Prospectus Supplement, together with the U.S. Base Prospectus, is hereinafter called the “U.S. Preliminary Prospectus”.

In addition, the Underwriters also understand that the Corporation will (i) prepare and file, as promptly as practicable and in any event by 5:00 p.m. (Eastern time) on February 23, 2024, with the Canadian Securities Commissions, in accordance with the Shelf Procedures, a final prospectus supplement setting forth the Shelf Information (including any Documents Incorporated by Reference therein and any supplements or amendments thereto, the “Canadian Prospectus Supplement”, and, together with the Canadian Base Shelf Prospectus, the “Canadian Prospectus”), and (ii) prepare and file with the SEC, within one Business Day following the filing of the Canadian Prospectus Supplement with the Canadian Securities Commissions, in accordance with General Instruction II.L of Form F-10, the Canadian Prospectus Supplement, with such deletions therefrom and additions or changes thereto as are permitted or required by Form F-10 and the applicable rules and regulations of the SEC (the “U.S. Prospectus Supplement”, and together with the U.S. Base Prospectus, the “U.S. Prospectus”). The information, if any, included in the Canadian Prospectus Supplement that is omitted from the Canadian Base Shelf Prospectus for which a Prospectus Receipt has been obtained, but that is deemed under the Shelf Procedures to be incorporated by reference in the Canadian Base Shelf Prospectus as of the date of the Canadian Prospectus Supplement, is referred to herein as the “Shelf Information”. The U.S. Prospectus Supplement and the Canadian Prospectus Supplement are hereinafter collectively referred to as the “Prospectus Supplements” and the U.S. Prospectus and the Canadian Prospectus are hereinafter collectively sometimes referred to as the “Prospectuses”.

Any reference herein to any “amendment” or “supplement” to the Canadian Base Shelf Prospectus, the Canadian Prospectus, the U.S. Base Prospectus or the U.S. Prospectus, shall be deemed to refer to and include (i) the filing of any document with the Canadian Securities Commissions or the SEC after the date of such Canadian Base Shelf Prospectus, Canadian Prospectus, U.S. Base Prospectus or U.S. Prospectus, as the case may be, which is incorporated therein by reference or is otherwise deemed to be a part thereof or included therein by the U.S. Securities Act or Canadian Securities Laws, as applicable, and (ii) any such document so filed.

The U.S. Preliminary Prospectus, as supplemented by an Issuer Free Writing Prospectus (as defined herein), if any, and the information listed in Schedule “C” hereto, taken together, are hereinafter referred to as the “Pricing Disclosure Package”. For purposes of this Agreement, the “Applicable Time” is 9:10 a.m. (Eastern time) on February 23, 2024.

The Corporation and the Underwriters agree that (i) any offers or sales of the Offered Shares in Canada will be conducted through the Underwriters, or one or more affiliates of the Underwriters, duly registered in compliance with applicable Canadian Securities Laws; and (ii) any offers or sales of the Offered Shares in the United States will be conducted through the Underwriters, or one or more affiliates of the Underwriters, duly registered as a broker-dealer in compliance with applicable U.S. Securities Laws (as defined herein) and the requirements of the Financial Industry Regulatory Authority, Inc. (“FINRA”).

In consideration of the services rendered and to be rendered by the Underwriters hereunder, the Corporation hereby agrees to pay to BMO Capital Markets, on behalf of the Underwriters, at the Closing Time (as defined herein), and at the Option Closing Time (as defined herein), if any, a cash fee equal to 4.0% of the aggregate gross proceeds of the Offering (the “Underwriting Fee”), the payment of such fee to be reflected by the Underwriters making payment of the gross proceeds of the sale of the Firm Shares or the Additional Shares, as the case may be, to the Corporation less the amount of the Underwriting Fee. Payment of the Underwriting Fee shall be inclusive of a 5.0% “work fee” payable to BMO Capital Markets.

This Agreement shall be subject to the following terms and conditions:

Where used in this Agreement or in any amendment hereto, the following terms shall have the following meanings, respectively:

“Additional Shares” has the meaning given to it in the second paragraph of this Agreement;

“affiliate” has the meaning given to it in the OBCA;

“Agreement” means the agreement resulting from the acceptance by the Corporation of the offer made by the Underwriters by this underwriting agreement;

“Applicable Securities Laws” means the Canadian Securities Laws and the U.S. Securities Laws;

“Applicable Time” has the meaning given to it in the seventh paragraph of this Agreement;

“Authorizations” has the meaning given to it in Section 7(33);

“BMO Capital Markets” has the meaning given to it in the first paragraph of this Agreement;

“Business Day” means any day, other than a Saturday or Sunday, on which banks are open for business in Toronto, Ontario, and New York, New York;

“Canadian Base Shelf Prospectus” has the meaning given to it in the third paragraph of this Agreement;

“Canadian Offering Documents” means each of the Canadian Prospectus and any Canadian Prospectus Amendment, including the Documents Incorporated by Reference and any marketing materials;

“Canadian Preliminary Prospectus Supplement” has the meaning given to it in the third paragraph of this Agreement;

“Canadian Prospectus” has the meaning given to it in the fifth paragraph of this Agreement;

“Canadian Prospectus Amendment” means any amendment to the Canadian Prospectus, including the Documents Incorporated by Reference;

“Canadian Prospectus Supplement” has the meaning given to it in the fifth paragraph of this Agreement;

“Canadian Securities Commissions” means the securities regulatory authorities in each of the Qualifying Jurisdictions;

“Canadian Securities Laws” means all applicable securities laws of each of the Qualifying Jurisdictions and the respective rules and regulations under such laws together with applicable published national, multilateral and local policy statements, instruments, notices, blanket orders and rulings of the securities regulatory authorities in the Qualifying Jurisdictions including, but not limited to, the WKSI Blanket Orders;

“CDS” means CDS Clearing and Depository Services Inc.;

“Claims” has the meaning given to it in Section 9;

“Closing Date” has the meaning given to it in Section 13;

“Closing Time” has the meaning given to it in Section 13;

“Commission” means the Ontario Securities Commission;

“Corporation” has the meaning given to it in the first paragraph of this Agreement;

“Corporation Contract” has the meaning given to it in Section 7(24);

“Credit Facility” has the meaning given to it in Section 7(3);

“Debt Instrument” means any material loan, bond, debenture, promissory note or other instrument evidencing indebtedness (demand or otherwise) for borrowed money, to which the Corporation or any of the Subsidiaries is a party or by which any of their property or assets are bound;

“Distribution” means “distribution” or “distribution to the public” as those terms are defined in the Canadian Securities Laws, except for where otherwise specified in this Agreement;

“Documents Incorporated by Reference” means all interim and annual financial statements, management’s discussion and analysis, business acquisition reports, management information circulars, annual information forms, material change reports, marketing materials and other documents that are or are deemed or required by Applicable Securities Laws to be incorporated by reference in the Offering Documents, as applicable, except to the extent that such documents, or certain parts thereof, are modified or superseded by a statement contained in the Prospectuses or Prospectus Supplements or any other document subsequently filed that is also incorporated by reference with the Prospectuses;

“EDGAR” means the SEC’s Electronic Document Gathering and Retrieval System;

“Employee Plans” has the meaning given to it in Section 7(35);

“Encumbrance” means any encumbrance of whatever kind or nature, regardless of form, whether or not registered or registrable and whether or not consensual or arising by law (statutory or otherwise), including any mortgage, lien, charge, pledge or security interest, whether fixed or floating, or any assignment, lease, option, right of pre-emption, right of first refusal, acquisition right, privilege, easement, right of way, servitude, restrictive covenant, right of use or any other right or claim of any kind or nature whatsoever which affects ownership or possession of, or title to, any interest in, or right to use or occupy property or assets;

“Environmental Laws” has the meaning given to it in Section 7(34);

“Financial Statements” means the audited consolidated financial statements of the Corporation as at December 31, 2023, the related notes thereto and the independent auditors’ report thereon;

“FINRA” has the meaning given to it in the eighth paragraph of this Agreement;

“Firm Shares” has the meaning given to it in the first paragraph of this Agreement;

“Foreign Corruption Laws” has the meaning given to it in Section 7(28);

“Form F-X” has the meaning given to it in the fourth paragraph of this Agreement;

“Governmental Entity” means any (i) multinational, federal, provincial, territorial, state, regional, municipal, local or other government, governmental or public department, central bank, court, tribunal, arbitral body, commission, board, bureau or agency, domestic or foreign; (ii) subdivision, agent, commission, board, or authority of any of the foregoing; or (iii) quasi-governmental or private body exercising any regulatory, expropriation or taxing authority under, or for the account of, any of the foregoing;

“Hazardous Materials” has the meaning given to it in Section 7(34);

“Indemnified Expenses” has the meaning given to it in Section 9(4);

“Indemnified Party” or “Indemnified Parties” has the meaning given to it in Section 9;

“Intellectual Property Rights” has the meaning given to it in Section 7(32);

“Issuer Free Writing Prospectus” means an “issuer free writing prospectus” as defined in Rule 433 under the U.S. Securities Act relating to the Offered Shares that (i) is required to be filed with the SEC by the Corporation, (ii) is a “road show that is a written communication” within the meaning of Rule 433(d)(8)(i) under the U.S. Securities Act whether or not required to be filed with the SEC or (iii) is exempt from filing pursuant to Rule 433(d)(5)(i) under the U.S. Securities Act because it contains a description of the Offered Shares or of the Offering that does not reflect the final terms, in each case in the form filed or required to be filed with the SEC or, if not required to be filed, in the form retained in the Corporation’s records pursuant to Rule 433(g) under the U.S. Securities Act;

“IT Systems and Data” has the meaning given to it in Section 7(45);

“Joint Bookrunners” has the meaning given to it in the first paragraph of this Agreement;

“Liability Amount” has the meaning given to it in Section 9(4);

“marketing materials” has the meaning given to it in NI 41-101;

“Material Adverse Effect” means any change, effect, event, occurrence, circumstance, violation or inaccuracy, as the case may be, that has or would reasonably be expected to have a material adverse effect on the business, assets, properties, affairs, liabilities (absolute, accrued, contingent or otherwise), capitalization, condition (financial or otherwise), results of operations, cash flows, control or management of the Corporation and the Subsidiaries (on a consolidated basis); or (ii) result in any Offering Document containing a misrepresentation;

“Material Agreement” means any Debt Instrument, contract, commitment, agreement (written or oral), instrument, lease, license, or other document (written or oral), to which the Corporation or the Subsidiaries are a party and which is material to the Corporation and the Subsidiaries (on a consolidated basis);

“material change” has the meaning given to such term under Applicable Securities Laws or any of them;

“material fact” has the meaning given to such term under Applicable Securities Laws;

“Material Subsidiaries” means Colliers International Holdings (USA) Inc., Colliers International EMEA Holdings Limited, Colliers Macaulay Nicolls Inc., Colliers International USA, LLC, Colliers Investment Management Holdings, Inc., Colliers Macaulay Nicolls (Cyprus) Ltd., Colliers International Holdings Limited, CI Holdings (USA), LLC, Colliers International WA, LLC, Harrison Street Real Estate Capital, LLC, and Colliers Engineering & Design Inc., as set forth in Schedule “A” of this Agreement;

“misrepresentation” has the meaning given to such term under Applicable Securities Laws;

“MJDS” has the meaning given to it in the fourth paragraph of this Agreement;

“Money Laundering Laws” has the meaning given to it in Section 7(30);

“Multiple Voting Shares” means the multiple voting shares in the capital of the Corporation;

“Nasdaq” means the Nasdaq Global Select Market of the Nasdaq Stock Market LLC;

“NI 41-101” means National Instrument 41-101 – General Prospectus Requirements;

“NI 44-101” means National Instrument 44-101 – Short Form Prospectus Distributions;

“NI 44-102” means National Instrument 44-102 – Shelf Distributions;

“NI 51-102” means National Instrument 51-102 – Continuous Disclosure Obligations;

“NI 52-109” means National Instrument 52-109 – Certification of Disclosure in Issuer’s Annual and Interim Filings;

“OBCA” means the Business Corporations Act (Ontario);

“OFAC” has the meaning given to it in Section 7(30);

“Offered Shares” has the meaning given to it in the second paragraph of this Agreement;

“Offering” means the sale of Offered Shares pursuant to this Agreement;

“Offering Documents” means the Canadian Offering Documents and the U.S. Offering Documents;

“Offering Jurisdictions” means the United States and the Qualifying Jurisdictions;

“Offering Price” has the meaning given to it in the first paragraph of this Agreement;

“Option Closing Date” has the meaning given to it in Section 15(1);

“Option Closing Time” has the meaning given to it in Section 15(1);

“Over-Allotment Option” has the meaning given to it in the second paragraph of this Agreement;

“Person” shall be interpreted broadly and include any individual (whether acting as an executor, trustee administrator, legal representative or otherwise), partnership, limited partnership, limited liability partnership, corporation, limited liability company, unlimited liability company, joint stock company, trust, unincorporated association, joint venture or any other entity;

“Preference Shares” has the meaning given to it in Section 7(4);

“Pricing Disclosure Package” has the meaning given to it in the seventh paragraph of this Agreement;

“Prospectus Receipt” means the receipt issued by the Commission for the Canadian Base Shelf Prospectus and any Canadian Prospectus Amendment, as the case may be;

“Prospectus Supplements” has the meaning given to it in the fifth paragraph of this Agreement;

“Prospectuses” has the meaning given to it in the fifth paragraph of this Agreement;

“Purchasers” means, collectively, each of the purchasers of the Offered Shares arranged by the Underwriters pursuant to the Offering;

“Qualifying Jurisdictions” means each of the provinces and territories of Canada other than Québec, and such other jurisdictions to which the Underwriters and the Corporation may agree;

“Registration Statement” has the meaning given to it in the fourth paragraph of this Agreement;

“Returns” has the meaning given to it in Section 7(37);

“Sanctions” has the meaning given to it in Section 7(30);

“SEC” has the meaning given to it in the fourth paragraph of this Agreement;

“SEDAR+” means the System for Electronic Document Analysis and Retrieval +;

“Selling Firm” has the meaning given to it in Section 2(1);

“Shelf Information” has the meaning given to it in the fifth paragraph of this Agreement;

“Shelf Procedures” means NI 44-101 and NI 44-102;

“Senior Notes due 2028” has the meaning given to it in Section 7(3);

“Senior Notes due 2031” has the meaning given to it in Section 7(3);

“Standard Listing Conditions” has the meaning given to it in Section 14(1)(e);

“Structured Accounts Receivable Facility” has the meaning given to it in Section 7(3);

“Subordinate Voting Shares” means the subordinate voting shares in the capital of the Corporation;

“Subsidiaries” has the meaning ascribed to such term in the Securities Act (Ontario).

“Supplementary Material” means, collectively, any amendment to the Offering Documents and any amendment or supplemental prospectus or ancillary materials that may be filed by or on behalf of the Corporation under Applicable Securities Laws relating to the Offering and/or the distribution of the Offered Shares;

“Taxes” has the meaning given to it in Section 7(37);

“template version” has the meaning ascribed to such term in NI 41-101 and includes any revised template version of marketing materials as contemplated by NI 41-101;

“Term Sheet” means the following documents that constitute the template version of marketing materials and were filed in accordance with NI 44-101: the term sheet dated February 22, 2024 entitled “Colliers International Group Inc. – Treasury Offering of Subordinate Voting Shares”;

“TSX” means the Toronto Stock Exchange;

“Underwriters” has the meaning given to it in the first paragraph of this Agreement;

“Underwriters’ Information” has the meaning given to it in Section 9(1);

“Underwriting Fee” has the meaning given to it in the ninth paragraph of this Agreement;

“United States” means the United States of America, its territories and possessions, any State of the United States and the District of Columbia;

“U.S. Amended Prospectus” means any amendment or supplement to the U.S. Prospectus;

“U.S. Base Prospectus” has the meaning given to it in the fourth paragraph of this Agreement;

“U.S. Exchange Act” means the United States Securities Exchange Act of 1934, as amended;

“U.S. GAAP” has the meaning given to it in Section 7(15);

“U.S. Offering Documents” means the Registration Statement, any U.S. Registration Statement Amendment, the U.S. Prospectus, any U.S. Amended Prospectus and the Pricing Disclosure Package;

“U.S. Preliminary Prospectus” has the meaning given to it in the fourth paragraph of this Agreement;

“U.S. Preliminary Prospectus Supplement” has the meaning given to it in the fourth paragraph of this Agreement;

“U.S. Prospectus” has the meaning given to it in the fifth paragraph of this Agreement;

“U.S. Prospectus Supplement” has the meaning given to it in the fifth paragraph of this Agreement;

“U.S. Registration Statement Amendment” means any amendment to the Registration Statement and any post-effective amendment to the Registration Statement filed with the SEC during the Distribution of the Offered Shares;

“U.S. Securities Act” has the meaning given to it in the fourth paragraph of this Agreement;

“U.S. Securities Laws” means all applicable United States securities laws, including, without limitation, the U.S. Securities Act, the U.S. Exchange Act and the rules and regulations promulgated thereunder; and

“WKSI Blanket Orders” means, collectively, CSA Staff Notice 44-306 – Blanket Orders Exempting Well-known Seasoned Issuers from Certain Prospectus Requirements, Ontario Instrument 44-501 – Exemption from Certain Prospectus requirements for Well-known Seasoned Issuers (Interim Class Order), OSC Rule 44-502 – Extension to Ontario Instrument 44-501 – Certain Prospectus Requirements for Well-known Seasoned Issuers and the equivalent blanket orders and rules adopted by the Canadian Securities Commissions.

Schedule “A” – Material Subsidiaries

Schedule “B” – Matters to be Addressed in the Corporation’s Canadian and U.S. Counsel Opinion

Schedule “C” – Pricing Terms Included in the Pricing Disclosure Package

Schedule “D” – Form of Lock-Up Agreement

Schedule “E” – Lock-up Parties

provided, that with respect to (i) clauses (a) and (c) of this Section 5(1), if the documents are publicly available on SEDAR+, they shall be deemed to have been delivered to the Underwriters as required by this Section 5(1); and (ii) clauses (b) and (d) of this Section 5(1), if the documents are publicly available on EDGAR, they shall be deemed to have been delivered to the Underwriters as required by this Section 5(1).

The Corporation will make all necessary filings, obtain all necessary consents and approvals (if any) and pay all filing fees required to be paid in connection with the transactions contemplated by this Agreement. The Corporation will qualify the Offered Shares for offer and sale under the Applicable Securities Laws of the Offering Jurisdictions and maintain such qualifications in effect for so long as required for the Distribution of the Offered Shares; provided, however, that (i) the Corporation shall not be obligated to make any material filing, file any prospectus, registration statement or similar document, consent to service of process, or qualify as a foreign corporation or as a dealer in securities in any of such other jurisdictions, or subject itself to taxation in respect of doing business in any of such other jurisdictions in which it is not otherwise so subject, or become subject to any additional periodic reporting or continuous disclosure obligations in such other jurisdictions and (ii) the Underwriters and the Selling Firms shall comply with the applicable laws in any such designated jurisdiction in making offers and sales of Offered Shares therein.

The Corporation represents and warrants to each of the Underwriters as set forth below and acknowledges that the Underwriters are relying on such representations and warranties in entering into this Agreement.

and to reimburse each Indemnified Party forthwith, upon demand, for any legal or other expenses reasonably incurred by such Indemnified Party in connection with any Claim; except that, if and to the extent that a court of competent jurisdiction in a final judgement that has become non-appealable determines that a Claim referred to in paragraph (d) or (e) above was caused by or resulted from the fraud, gross negligence or wilful misconduct of the Indemnified Party claiming indemnity, such Indemnified Party shall reimburse any funds advanced by the Corporation to such Indemnified Party in respect of such Claim and thereafter this Section 9(1) shall cease to apply to such Indemnified Party in respect of such Claim.

and the Corporation will use its commercially reasonable efforts to prevent the issuance of any order referred to in subparagraph 10(1)(b)(i) above or subparagraph 10(1)(b)(ii) above and, if any such order is issued, use its commercially reasonable efforts to obtain the withdrawal thereof at the earliest possible time;

The Corporation agrees that the conditions contained in this Agreement will be complied with insofar as the same relate to acts to be performed or caused to be performed by the Corporation. It is understood that the Underwriters may waive, in whole or in part, or extend the time for compliance with, any of such terms and conditions without prejudice to the rights of the Underwriters in respect of any such terms and conditions or any other or subsequent breach or non-compliance, provided that to be binding on the Underwriters any such waiver or extension must be in writing and signed by the Underwriters.

The closing of the purchase and sale of the Firm Shares herein provided for shall be completed electronically at 8:00 a.m. (Eastern time) on February 28, 2024, or such other date and/or time as may be agreed upon in writing by the Corporation and the Underwriters (respectively, the “Closing Time” and the “Closing Date”).

The Corporation will be solely responsible for all its expenses related to the Offering, including all fees and disbursements of its counsel, its “out of pocket” costs, printing costs and filing fees, whether or not the Offering is completed. Each Underwriter will be solely responsible for all its expenses related to the Offering, including all fees and disbursements of its counsel and its “out of pocket” costs, provided that if the Offering is not completed due to any breach or default on the Corporation’s part of its obligations hereunder, the Corporation will reimburse each Underwriter for all of its documents costs and expenses reasonably incurred.

The Corporation acknowledges and agrees that (a) the purchase and sale of the Offered Shares pursuant to this Agreement, including the determination of the Offering Price of the Offered Shares and any related discounts and commissions, is an arm’s-length commercial transaction between the Corporation, on the one hand, and the several Underwriters, on the other hand, (b) in connection with the Offering and the process leading to such transaction each Underwriter is and has been acting solely as a principal and is not the agent or fiduciary of the Corporation or its shareholders, creditors, employees or any other party, (c) no Underwriter has assumed or will assume an advisory or fiduciary responsibility in favour of the Corporation with respect to the Offering or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Corporation on other matters) and no Underwriter has any obligation to the Corporation with respect to the Offering except the obligations expressly set forth in this Agreement, (d) the Underwriters and their respective affiliates may be engaged in a broad range of transactions that involve interests that differ from those of the Corporation, and (e) the Underwriters have not provided any legal, accounting, regulatory or tax advice with respect to the Offering and the Corporation has consulted its own legal, accounting, regulatory and tax advisors to the extent it deems appropriate.

Any notice to be given hereunder shall be in writing and may be given by email or by hand delivery and shall, in the case of notice to the Corporation, be addressed and emailed or delivered to:

Colliers International Group Inc.

1140 Bay Street, Suite 4000

Toronto, Ontario

M5S 2B4

Attention:       Christian Mayer, Chief Financial Officer

Email:              [Redacted]

with a copy to (such copy not to constitute notice):

Torys LLP

79 Wellington St. W., 33rd Floor
Toronto, Ontario
M5K 1N2

Attention:       Rima Ramchandani

Email:              [Redacted]

-and-

Torys LLP

1114 Avenue of the Americas, 23rd Floor

New York, New York

10036-7703

Attention:       Chris Bornhorst

Email:              [Redacted]

and in the case of the Joint Bookrunners (on behalf of the Underwriters), be addressed and emailed or delivered to each of:

BMO Nesbitt Burns Inc.

100 King Street West, 4th Floor
Toronto, Ontario
M5X 1A1

Attention:       Jeff Watchorn

Email:              [Redacted]

-and-

J.P. Morgan Securities Canada Inc.
66 Wellington Street West, Floor 45
Toronto, Ontario
M5K 1E7

Attention:       Brandon Speck
Email:              [Redacted]

with a copy to (such copy not to constitute notice):

Blake, Cassels & Graydon LLP
199 Bay Street, Suite 4000
Toronto, Ontario

M5L 1A9

Attention:       Tim Andison / Liam Churchill

Email:              [Redacted]

-and-

Paul, Weiss, Rifkind, Wharton & Garrison LLP

77 King Street West, Suite 3100

Toronto, Ontario

M5K 1J3

Attention:       Christopher Cummings

Email:              [Redacted]

The Corporation and the Joint Bookrunners may change their respective addresses for notice by notice given in the manner referred to above.

All steps which must or may be taken by the Underwriters in connection with this Underwriting Agreement, with the exception of the matters contemplated by Section 9 and Section 12, shall be taken by the Joint Bookrunners on the Underwriters’ behalf and the execution of the Agreement by the Underwriters shall constitute the Corporation’s authority for accepting notification of any such steps from, and for giving notice to, and for delivering any electronic deposits or definitive certificate(s) representing the Offered Shares to, or to the order of, the Joint Bookrunners.

The representations, warranties, obligations and agreements of the Corporation and of the Underwriters contained herein or delivered pursuant to this Agreement shall survive the purchase by the Underwriters of the Offered Shares for a period of three years following the Closing Date and shall continue in full force and effect notwithstanding any subsequent disposition by the Underwriters of the Offered Shares and the Underwriters shall be entitled to rely on the representations and warranties of the Corporation contained in or delivered pursuant to this Agreement notwithstanding any investigation which the Underwriters may undertake or which may be undertaken on the Underwriters’ behalf.

In connection with the distribution of the Offered Shares, the Underwriters (or any of them) may effect transactions which stabilize or maintain the market price of the Subordinate Voting Shares at levels other than those which might otherwise prevail in the open market, but in each case as permitted by Applicable Securities Laws. Such stabilizing transactions, if any, may be discontinued by the Underwriters at any time.

Any and all previous agreements with respect to the purchase and sale of the Offered Shares, whether written or oral, including for the avoidance of doubt, the letter agreement dated February 22, 2024 between the Corporation and BMO Capital Markets, are terminated and this Agreement constitutes the entire agreement between the Corporation and the Underwriters with respect to the purchase and sale of the Offered Shares.

Neither the Corporation nor the Underwriters shall make any public announcement concerning the appointment of the Underwriters or the Offering without the consent of the other parties, acting reasonably, and any public announcements shall be made in compliance with Applicable Securities Laws. After completion of the Offering, the Underwriters shall be entitled to place advertisements in financial and other newspapers and journals at their own expense describing their services hereunder.

This Agreement shall be governed by and construed in accordance with the laws of the Province of Ontario and the federal laws of Canada applicable therein.

Certain of the Underwriters or affiliates thereof, each own or control an equity interest in TMX Group Limited (“TMX Group”) and may have a nominee director serving on the TMX Group’s board of directors. As such, such investment dealers may be considered to have an economic interest in the listing of securities on any exchange owned or operated by TMX Group, including the Toronto Stock Exchange. No Person is required to obtain products or services from TMX Group or its affiliates as a condition of any such dealer supplying or continuing to supply a product or service.

Time shall be of the essence of this Agreement. This Agreement may be executed in counterparts, each of which when so executed shall be deemed to be an original and such counterparts together shall constitute one and the same instrument.

If the foregoing is in accordance with your understanding and is agreed to by you, will you please confirm your acceptance by signing the enclosed copies of this Agreement at the place indicated and returning the same to us.

Yours truly,

The foregoing is in accordance with our understanding and is accepted by us.

SCHEDULE “A”

MATERIAL SUBSIDIARIES

SCHEDULE “B”

MATTERS TO BE ADDRESSED IN THE CORPORATION’S
COUNSEL OPINION

(a) The Corporation is a corporation duly incorporated and validly existing under the Business Corporations Act (Ontario);

(b) The Corporation has the requisite corporate power and capacity to own, lease and operate its properties and assets and to carry on its business as now conducted as described in the Canadian Prospectus and to execute and deliver the Underwriting Agreement and to carry out its obligations thereunder;

(c) The authorized capital of the Corporation consists of an unlimited number of preference shares (the “Preference Shares”), issuable in series, an unlimited number of Subordinate Voting Shares and an unlimited number of Multiple Voting Shares. Immediately prior to the closing of the Offering, no Preference Shares, 46,246,182 Subordinate Voting Shares and 1,325,694 Multiple Voting Shares were issued and outstanding;

(d) The Corporation has taken all necessary corporate action to (i) authorize the execution, delivery and performance of the Underwriting Agreement and (ii) authorize the delivery and, where applicable, execution and filing by the Corporation of the Prospectuses under the securities laws in each of the Qualifying Jurisdictions;

(e) The Corporation has taken all necessary corporate action to authorize the issuance, sale and delivery of the Offered Shares and when issued and delivered and upon receipt of payment in full therefor in accordance with the terms of the Underwriting Agreement, the Offered Shares will be outstanding as validly issued as fully paid and non-assessable subordinate voting shares in the capital of the Corporation;

(f) Subject to the Corporation fulfilling the conditions set forth in the TSX Confirmation Letter, the Offered Shares have been conditionally approved for listing on the TSX;

(g) The Underwriting Agreement has been duly executed and delivered by the Corporation and constitutes a legal, valid and binding obligation of the Corporation enforceable against the Corporation in accordance with its terms;

(h) TSX Trust Company is the duly appointed registrar and transfer agent for the Subordinate Voting Shares of the Corporation;

(i) All necessary documents have been filed, all requisite proceedings have been taken and all other legal requirements have been fulfilled by the Corporation under the Securities Act (Ontario), the Securities Act (Alberta), the Securities Act (Québec) and the regulations, rules, policy statements, notices, blanket rulings, decisions and orders thereunder (collectively, “Securities Laws”) to qualify the Offered Shares for distribution and sale to the public in the Provinces of Ontario, Alberta and Québec through investment dealers or brokers registered in the appropriate category of registration under the applicable Securities Laws who comply with the relevant provisions of such laws and the terms of such registration;

(j) The Corporation is a “reporting issuer”, or its equivalent, under the Securities Laws of the Provinces of Alberta, Ontario and Québec, and is not noted in default on the Reporting Issuer List;

(k) The attributes of the Offered Shares conform, in all material respects, with the description thereof contained under the heading “Description of Share Capital” in the Prospectuses;

(l) Subject to the qualifications, assumptions, limitations, and understandings set out in the Canadian Prospectus under the headings “Canadian Federal Income Tax Considerations” and “Eligibility For Investment”, insofar as the statements under such headings constitute statements of law, they have been reviewed, fairly summarize the matters described therein, and are accurate in all material respects;

(m) Subject to the assumptions, qualifications, and limitations referred to therein, the statements set out in the U.S. Prospectus under the caption “Certain United States Federal Income Tax Considerations”, insofar as they purport to constitute summaries of matters of United States federal income tax law or legal conclusions with respect thereto, constitute fair and accurate summaries of the matters described therein in all material respects;

(n) The Registration Statement, the Form F-X and the U.S. Prospectus, as of their respective dates, appear on their face to be appropriately responsive in all material respects to the requirements of the U.S. Securities Act and the rules and regulations of the SEC under the U.S. Securities Act, except for the financial statements, financial statement schedules and other financial data included or incorporated by reference in or omitted from any of them, as to which we express no opinion;

(o) The issuance and sale of the Offered Shares and the execution and delivery by the Corporation of the Underwriting Agreement and the performance by the Corporation of its obligations thereunder will not (i) breach or result in a default under, and do not and will not conflict with any of the terms, conditions or provisions of the articles or by-laws of the Corporation, the Credit Facility or the agreements listed in Schedule I hereto, except where any such breach or default would not reasonably be expected to have a Material Adverse Effect or (ii) violate any law, rule or regulation or any judgment, order or decree of any New York or United States federal court or governmental authority binding upon the Corporation, except where any such violation would not reasonably be expected to have a Material Adverse Effect;

(p) No authorization, consent, permit or approval of, or other action by, or filing with a notice to, or registration or qualification with, any U.S. federal or New York governmental agency or authority, executive, legislative, judicial, administrative or regulatory body, court tribunal or other similar entity having jurisdiction over the Corporation is required in connection with the issuance and sale of the Offered Shares by the Corporation, the execution and delivery by the Corporation of the Underwriting Agreement and the performance of its obligations thereunder, except such as may have been made or obtained and except as may be required by FINRA or under U.S. state securities or “blue sky” laws, as to which we express no opinion;

(q) The Corporation is not and, after giving effect to the Offering, and the application of the net proceeds therefrom as described in the Pricing Disclosure Package and the U.S. Prospectus under the heading “Use of Proceeds,” will not be required to be, registered as an investment company under the Investment Company Act and the rules and regulations of the SEC promulgated thereunder;

(r) Each of the Delaware Corporations is validly existing and in good standing under the laws of the State of Delaware;

(s) Each of the Delaware Corporations has the requisite corporate power under the laws of the State of Delaware to carry on its business as presently carried on;

(t) Each of the Delaware LLCs is validly existing and in good standing under the laws of the State of Delaware; and

(v) Each of the Delaware LLCs has the requisite limited liability company power under the laws of the State of Delaware to carry on its business as presently carried on.

Schedule I

SCHEDULE “C”

PRICING TERMS INCLUDED IN PRICING DISCLOSURE PACKAGE

The price per share for the Subordinate Voting Shares is US$121,00.

The number of Subordinate Voting Shares purchased by the Underwriters is 2,479,500.

The Corporation has granted the Underwriters an option, exercisable, in whole or in part, at any time until and including 30 days following the closing of the Offering, to purchase up to an additional 371,925 Subordinate Voting Shares at US$121.00 per Subordinate Voting Share to cover over-allotments, if any, and for market stabilization purposes.

The Underwriters receive a cash commission equal to the Underwriting Fee.

Issuer Free Writing Prospectuses

None.

SCHEDULE “D”

FORM OF LOCK-UP AGREEMENT

SCHEDULE “E”

LOCK-UP PARTIES

Exhibit 99.2

79 Wellington St. W., 30th Floor Box 270, TD South Tower Toronto, Ontario M5K 1N2 Canada P. 416.865.0040 | F. 416.865.7380   www.torys.com

February 26, 2024

Colliers International Group Inc.

1140 Bay Street, Suite 4000

Toronto, Ontario

M5S 2B4

Dear Sirs/Mesdames:

Re: Consent of Torys LLP

We hereby consent to the reference to our name under the heading “Legal Matters” and to the reference to our name and to the use of our opinions under the heading “Canadian Federal Income Tax Considerations” in the Prospectus Supplement dated February 23, 2024 relating to the offering by Colliers International Group Inc. (the “Corporation”) of 2,479,500 Subordinate Voting Shares of the Corporation, which has been filed under the registration statement of the Corporation on Form F-10 (File No. 333-277184). In giving this consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended.

Yours truly,

/s/ Torys LLP

Exhibit 99.3

February 26, 2024

VIA EDGAR

Colliers International Group Inc.

1140 Bay St., Suite 4000

Toronto, Ontario

M5S 2B4

Dear Sirs/Mesdames:

Re:   Colliers International Group Inc. (the “Company”) – Consent for Prospectus Supplement

We refer to the Company’s prospectus supplement dated February 23, 2024 (the “Prospectus Supplement”), to the short form base shelf prospectus dated February 20, 2024, forming part of the Registration Statement on Form F-10 (Registration No. 333-277184) filed by the Company with the U.S. Securities and Exchange Commission.

We hereby consent to the reference to our firm name under the heading “Legal Matters”, and to the use of our legal opinion under the heading “Canadian Federal Income Tax Considerations”, which opinion is provided as of the date of the Prospectus Supplement.

In giving this consent, we do not thereby admit that we come within the category of persons whose consent is required by the Securities Act of 1933, as amended, or the rules and regulations promulgated thereunder.

Yours very truly,

/s/ Blake, Cassels & Graydon LLP