Exhibit 99.1

Invitation to the

2026 Annual General Meeting
of
WISeKey International Holding Ltd

Monday, June 29, 2026, 2 p.m. Swiss time
Homburger AG

Prime Tower, Hardstrasse 201

8005 Zurich, Switzerland

Admittance: 1:30 p.m.

Agenda Items

Swiss time The board of directors (the Board or the Board of Directors) of WISeKey International Holding Ltd (the Company) submits the following agenda items and proposals for resolution and approval by the Company’s shareholders at the Company’s Annual General Meeting (the AGM) to be held on June 29, 2026, 2 p.m. Swiss time, at the offices of Homburger AG, Prime Tower, Hardstrasse 201, 8005 Zurich, Switzerland:

Proposal of the Board of Directors: The Board of Directors proposes that the annual report 2025 (the Annual Report 2025), including the audited consolidated financial statements for the calendar year ending December 31 (“fiscal year”), 2025, and the audited statutory financial statements for fiscal year 2025, be approved.

Explanation: Pursuant to article 698 para. 2 items 3 and 4 of the Swiss Code of Obligations (CO) and article 8 para. 2 item nos. 5 and 6 of the Company’s articles of association (the Articles of Association), shareholders must approve at the annual general meeting the management report, the audited consolidated financial statements and the audited statutory financial statements for the relevant fiscal year. You can find the Annual Report 2025 (including the management report) and the audited consolidated financial statements and the audited statutory financial statements for fiscal year 2025 at https://www.wisekey.com/company/investors/financial-reports/. Our auditor, BDO SA, Vernier, has issued unqualified audit reports on the audited consolidated financial statements and the audited statutory financial statements for fiscal year 2025.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 1.

Proposal of the Board of Directors: The Board of Directors proposes that the members of the Board of Directors and Messrs. Carlos Moreira (CEO) and John O’Hara (CFO), who served as members of the Executive Management in fiscal year 2025, be discharged from liability for activities during fiscal year 2025.

Explanation: Pursuant to article 698 para. 2 item 7 CO and article 8 para. 2 item no. 7 of our Articles of Association, the Board of Directors may propose to the general meeting of shareholders that the members of the Board of Directors and the Executive Management be discharged from liability. Discharge pursuant to the proposal is effective only with respect to facts that have been disclosed to shareholders and only binds shareholders who either voted in favour of the proposal or who acquired shares with knowledge that the shareholders have approved the proposal.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 2.

Proposal of the Board of Directors: The Board of Directors proposes that the total accumulated loss be carried forward.

Explanation: Pursuant to article 698 para. 2 item 4 CO and article 8 para. 2 item no. 6 of our Articles of Association, the general meeting of shareholders resolves on the appropriation of available earnings or the accumulated loss. The Board of Directors proposes that the entire net loss for fiscal year 2025 be carried forward.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 3.

Proposal of the Board of Directors: The Board of Directors proposes that the following seven currently serving directors be re-elected to the Board of Directors, each for a term extending until completion of the next Annual General Meeting:

In addition, the Board of Directors proposes the election of Andrew Forson as a new member of the Board of Directors for a term extending until completion of the next Annual General Meeting:

Explanation: Pursuant to article 698 para. 2 item 2 CO and article 8 para. 2 no. 2 of the Articles of Association, the annual re-election of the members of the Board of Directors after the expiry of their one-year term is the responsibility of the general meeting of shareholders. You can find biographical information on the members of the Board of Directors standing for re-election at this AGM at https://www.wisekey.com/company/corporate-governance/board-of-directors/.

Recommendation: The Board of Directors recommends you vote “FOR” the re-election of each of the seven current members of the Board of Directors and the election of Andrew Forson as a new member of the Board of Directors.

Proposal of the Board of Directors: The Board of Directors proposes that Carlos Moreira be re-elected as the Chairman of the Board of Directors for a term extending until completion of the next Annual General Meeting.

Explanation: Pursuant to article 698 para. 3 item 1, article 712 para. 1 CO and article 8 para. 2 no. 2 of the Articles of Association, shareholders elect the chair of the Board of Directors at the general meeting of shareholders. The statutory term of office is one year.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 5.

Proposal of the Board of Directors: The Board of Directors proposes that the following candidates be re-elected as members of the Nomination & Compensation Committee, each for a term extending until completion of the next Annual General Meeting:

Explanation: Pursuant to article 698 para. 3 item 2, article 733 para. 1 CO and article 8 para. 2 no. 2 of the Articles of Association, shareholders elect the members of the Nomination & Compensation Committee at the general meeting of shareholders. The statutory term of office is one year. Only members of the Board of Directors may be elected to the Nomination & Compensation Committee.

Recommendation: The Board of Directors recommends you vote “FOR” the re-election of each of these nominees as members of the Nomination & Compensation Committee.

Proposal of the Board of Directors: The Board of Directors proposes that BDO SA, Vernier, be re-elected as the Company’s auditor pursuant to the CO for a further one-year term, commencing on the date of the 2026 Annual General Meeting and terminating on the date of the 2027 Annual General Meeting.

Explanation: Pursuant to article 698 para. 2 item 2 CO and article 8 para. 2 no. 3 of the Articles of Association, the shareholders elect the auditor at a general meeting. BDO SA, Vernier, satisfies the applicable statutory independence requirements.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 7.

Proposal of the Board of Directors: The Board of Directors proposes that the law firm Anwaltskanzlei Keller AG, Zurich, be re-elected to serve as Independent Proxy at (and until completion of) the 2027 Annual General Meeting and at any extraordinary general meeting of shareholders of the Company that may be held prior to the 2027 Annual General Meeting.

Explanation: According to article 689c para. 1, article 698 para. 3 item 3 CO and article 8 para. 2 no. 4 of the Articles of Association, shareholders elect the independent proxy at the general meeting. The statutory term of office is one year. The law firm Anwaltskanzlei Keller AG, Zurich, has confirmed that it satisfies the applicable statutory independence requirements.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 8.

Proposal of the Board of Directors: The Board of Directors proposes that the compensation report, as included in the Annual Report 2025, be approved in a non-binding advisory vote.

Explanation: The majority of Swiss public companies asks shareholders to approve the variable compensation of the executive management prospectively (i.e., in relation to the next financial year). The Company follows this practice for the Executive Management. Under these circumstances, the Board of Directors must, in accordance with article 735 para. 3 item 4 CO, seek an advisory vote from shareholders on the compensation report in relation to the preceding financial year. The compensation report for fiscal year 2025 is part of the Annual Report 2025, which is available to shareholders on the Company’s website at https://www.wisekey.com/company/investors/financial-reports/. It explains the governance framework and the principles underlying the compensation structure at the Company. In addition, the compensation report sets out the remuneration of the Board of Directors and the Executive Management for 2025, as required under the CO.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 9.

Proposal of the Board of Directors: The Board of Directors proposes that the shareholders ratify an amount of CHF 2,000,000 as the maximum aggregate amount of compensation of the Board of Directors for the period between the 2026 Annual General Meeting and the 2027 Annual General Meeting.

Explanation: In accordance with article 698 para. 3 item 4, article 735 para. 1 CO and article 26 para. 1 letter a of the Articles of Association, the Board of Directors must submit the maximum aggregate amount of compensation of the Board of Directors to shareholders for approval. The proposed maximum aggregate compensation amount of the members of the Board of Directors for the 2026/2027 term has been calculated on the basis of a Board of Directors consisting of eight members and on the basis of the following compensation components: A fixed annual base fee for directorship or, as applicable, an increased fixed base fee for a director’s role as the chair of a Committee, together with an equity-based compensation for directorship or, as applicable, an increased base equity-based compensation for a director’s role as the chair of a Committee.

The Board of Directors’ proposed aggregate maximum compensation amount is the same amount as the one proposed and approved at the 2025 Annual General Meeting.

As announced, the Board of Directors intends to change the place of incorporation from Switzerland to the British Virgin Islands (BVI). The redomiciliation is proposed to be implemented through a cross-border merger of WISeKey International Holding Ltd with and into a wholly owned British Virgin Islands subsidiary, WISeKey Corp (WISeKey BVI). The proposed redomiciliation remains subject to various conditions, including regulatory and shareholder approvals, which WISeKey expects to seek in the third quarter of 2026. Should the proposed redomiciliation be completed, the Company will no longer be incorporated in Switzerland and will instead be governed by BVI law. As a consequence, the requirement under the shareholder resolution relating to the maximum aggregate compensation of the Board of Directors will no longer apply, as BVI law does not provide for an equivalent ratification or approval mechanism in this regard.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 10.1.

Proposal of the Board of Directors: The Board of Directors proposes that the shareholders ratify an amount of CHF 7,500,000 as the maximum aggregate amount of compensation of the Executive Management for fiscal year 2027.

Explanation: Pursuant to article 698 para. 3 item 4, article 735 para. 1 CO and article 26 para. 1 item 2 of the Articles of Association, the Board of Directors must submit the maximum aggregate compensation amount of the Executive Management to shareholders for approval.

As announced and explained under Agenda Item 10.1, the Board of Directors intends to change the place of incorporation from Switzerland to the BVI. The redomiciliation is proposed to be implemented through a cross-border merger of WISeKey International Holding Ltd with and into a wholly owned British Virgin Islands subsidiary, WISeKey Corp (“WISeKey BVI”). The proposed redomiciliation remains subject to various conditions, including regulatory and shareholder approvals, which WISeKey expects to seek in the third quarter of 2026. Should the proposed redomiciliation be completed, the Company will no longer be incorporated in Switzerland and will instead be governed by BVI law. As a consequence, the requirement under the shareholder resolution relating to the maximum aggregate compensation of the Board of Directors will no longer apply, as BVI law does not provide for an equivalent ratification or approval mechanism in this regard.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 10.2.

Proposal of the Board of Directors: The Board of Directors proposes that shareholders approve an increase in the maximum aggregate compensation amount for Executive Management for the fiscal year 2026, as previously approved at the 2025 Annual General Meeting, from CHF 6,000,000 to CHF 15,000,000.

Explanation: Following a comprehensive benchmarking exercise conducted by the Compensation Committee of both SEALSQ Corp (SEALSQ), the Company’s subsidiary whose shares are listed on the Nasdaq and which the Company controls through the special voting rights F shares, and the Company, the Company’s compensation framework was reviewed to better align with market practice among the Company’s peers. This review reflected the Board of Directors’ commitment to maintaining a rigorous, performance-driven approach to executive compensation. In light of SEALSQ’s exceptional operational and financial performance during 2025, including achievements in capital raising and an increase in shareholder value, the Board of SEALSQ and the Board of WISeKey approved a one-off exceptional performance bonus for the relevant members of Executive Management. This bonus is linked to the delivery of measurable outcomes benefiting shareholders, namely the growth in SEALSQ’s market capitalisation and the successful execution of its capital-raising program during the year ended December 31, 2025.

At the 2025 Annual General Meeting, shareholders approved a maximum aggregate compensation amount of CHF 6,000,000 for Executive Management for fiscal year 2026. As a result of the one-off bonus described above, the total consolidated compensation payable by WISeKey to its Executive Management for fiscal year 2026 would exceed this approved amount. The Board therefore seeks shareholder ratification for an increase of the previously approved maximum aggregate compensation amount.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 10.3.

Proposal of the Board of Directors: The Board of Directors proposes that shareholders approve an additional amount of compensation for Executive Management in respect of the fiscal year 2025, in the form of options relating to SEALSQ Ordinary Shares, supplementing the maximum aggregate compensation amount of CHF 6,000,000 approved by shareholders at the 2024 Annual General Meeting.

Explanation: During the course of late 2024 and 2025, WISeKey and its subsidiary SEALSQ experienced a period of significant market recognition, reflecting growing investor appreciation of the Group’s cybersecurity capabilities and the strategic positioning of SEALSQ within the rapidly expanding market for post-quantum and IoT security solutions. This was reflected in a material appreciation in SEALSQ’s share price during the year.

Against this backdrop, the Board of Directors and Compensation Committee commenced discussions in 2024 and subsequently resolved in March 2025 to grant options over Ordinary Shares to members of Executive Management as part of the Company’s performance-based compensation framework. The grant was intended to align the long-term interests of Executive Management with those of shareholders by linking a meaningful component of executive reward to the continued creation of shareholder value.

Under Swiss law and the Company’s Articles of Association, the aggregate compensation for Executive Management, including the fair value of equity-based awards such as options over Ordinary Shares at the time of grant, is subject to the maximum aggregate amount approved by shareholders. The option grants made in March 2025, when valued in accordance with applicable accounting and governance standards, result in the total aggregate compensation for Executive Management for fiscal year 2025 exceeding the CHF 6,000,000 authorization previously approved by shareholders at the 2024 Annual General Meeting. The Board therefore respectfully requests that shareholders ratify the additional compensation in the amount of CHF 1,530,301 arising from these grants.

Recommendation: The Board of Directors recommends you vote “FOR” this proposal number 10.4.

Organizational Information

Right to Participate and Vote | Admission Cards

After returning the enclosed registration and authorization form (the Registration and Authorization Form), shareholders will receive an admission card and voting material.

Shareholders recorded in the Company’s share register with voting rights as at June 22, 2026 (the Record Date) will be entitled to participate in, and vote at, the AGM. No registrations and de-registrations of registered shares will be made in the share register from the close of business on June 22, 2026 at 5:00 p.m. CEST to the opening of business on the day following the AGM.

Shareholders who sold their shares prior to the Record Date will not be able to attend and vote at the AGM. Shareholders who purchase shares between the Record Date and the conclusion of the AGM will not be able to attend the AGM and vote those shares at the AGM.

Appointment of Proxy & Independent Proxy

A shareholder recorded in the Company’s share register with voting rights as at the Record Date and therefore entitled to participate in, and vote at, the AGM may give written proxy for the AGM to a third party (who need not be a shareholder). Proxy holders will only be admitted to the AGM upon presentation of a valid admission card, a duly executed proxy and proper identification.

At the 2025 Annual General Meeting, the law firm Anwaltskanzlei Keller AG, Splügenstrasse 8, 8027 Zurich, Switzerland, was elected as Independent Proxy for a term expiring upon completion of the 2026 Annual General Meeting. Shareholders who want to exercise their voting rights through the Independent Proxy must authorize the Independent Proxy to do so on their behalf at the 2026 Annual General Meeting. Shareholders may instruct the Independent Proxy by post by returning the Registration and Authorization Form to the address indicated on such form or electronically. Electronic voting instructions may be given by accessing the website https://www.gvote.ch and then following the guidance being displayed on the computer screen. The personal access data required for registration can be found on the Registration and Authorization Form. Instructions can be given electronically to the Independent Proxy until June 24, 2026; 11:59 p.m. CEST.

Instructions to the Independent Proxy

Shares of holders who have voted electronically or timely submitted a properly executed Registration and Authorization Form by post and specifically indicated their votes will be voted by the Independent Proxy as indicated. Holders of shares who have voted electronically or timely submitted a properly executed Registration and Authorization Form by post but have not specifically indicated their votes, instruct the Independent Proxy to vote in accordance with the recommendations of the Board of Directors with regard to the items specified in the invitation to the 2026 Annual General Meeting.

If any modifications to agenda items or proposals identified in the invitation to the 2026 Annual General Meeting or other matters on which voting is permissible under Swiss law are properly presented at the 2026 Annual General Meeting for consideration, you instruct the Independent Proxy, in the absence of other specific instructions, to vote in accordance with the recommendations of the Board of Directors. As of the date of this publication, the Board of Directors is not aware of any such modifications or other matters proposed to come before the 2026 Annual General Meeting.

The completed Registration and Authorization Forms may be sent by post to:

Computershare Switzerland Ltd

WISeKey International Holding Ltd

Postfach

4601 Olten

Switzerland

We urge you to return your Registration and Authorization Form or to submit instructions to the Independent Proxy electronically as soon as reasonably possible. All Registration and Authorization Forms submitted by post must be received no later than on Monday, June 24, 2026. Please do not mail the Registration and Authorization Form if you choose to give your instructions to the Independent Proxy electronically.

Annual Report

The Annual Report 2025, including the consolidated and statutory financial statements of the Company for fiscal year 2025 and the Company’s compensation report for 2025, can be accessed on the Company’s website (https://www.wisekey.com/investors/financial-reports/). Copies of these materials may also be obtained free of charge by contacting our Corporate Secretary at our registered office, General-Guisan-Strasse 6, 6030 Zug, Switzerland, telephone number +41 (0)22 594 30 00.

Zug, May 29, 2026

WISeKey International Holding Ltd

For the Board of Directors

The Chairman

Carlos Moreira

Exhibit 99.2

Registration and Authorization Form Annual General Meeting of WISeKey International Holding Ltd Monday, June 29, 2026 at 2:00 p.m. CEST Homburger AG Hardstrasse 201 8005 Zurich Admittance: 1:30 p.m. CEST Registration (admission cards will be sent starting from June 24, 2026) I hereby register to attend the Annual General Meeting and ask you to issue an admission card, together with the voting material, in my name. I hereby authorize that, at the Annual General Meeting, my shares (as well as any further shares registered in my name before the closing of the share register) be represented at the Annual General Meeting and the voting rights attached to my shares be exercised by: the Independent Proxy, Anwaltskanzlei Keller AG, Splügenstrasse 8, CH-8002 Zurich, Switzerland. To the extent that I do not mark boxes (see overleaf), thereby giving specific instructions, I instruct the Independent Proxy, by signing this form, to exercise my voting rights in favor of the proposals of the Board of Directors for all agenda items as well as any modified agenda items, proposals or other matters on which voting is permissible under Swiss law and which are properly presented at the Annual General Meeting. The Board of Directors recommends a vote in favor of all agenda items and proposals. a third party as representative. If you tick this box, you will be provided with the admission card and a proxy. To authorize the third party as a representative, you are asked to fill in the admission card and the proxy, to sign both documents and to hand them over to the third party representative. Instead of using this form you may authorize and give your instructions to the Independent Proxy until June 24, 2026 electronically, by accessing the website www.gvote.ch and then following the guidance displayed on your computer screen. Your personal access data for registration are: Electronic issuance of power of attorney Internet: Username: Password: www.gvote.ch Please send this form to Computershare Switzerland Ltd, WISeKey International Holding Ltd, Postfach, 4601 Olten, Switzerland, using the enclosed envelope. The completed form must be received no later than on June 24, 2026. Date: _______________________ Signature: ________________________________ *500* Number of shares: 362/DE/12 AA P.P.

CH-4601 Olten A-PRIORITY 12 Voting Instructions to the Independent Proxy In favor Against Abstention Item 1 Approval of the Annual Report 2025 of WISeKey International Holding Ltd, Including the Audited Consolidated Financial Statements for Fiscal Year 2025 and the Audited Statutory Financial Statements for Fiscal Year 2025 Item 2 Discharge of the Members of the Board of Directors and the Executive Management from Liability for Activities During Fiscal Year 2025 Item 3 Appropriation of Accumulated Loss for Fiscal Year 2025 Item 4 Re-election of 7 Members of the Board of Directors and Election of 1 New Member of the Board of Directors, all for a Term Extending Until Completion of the Next Annual General Meeting 4.1 Re-election of Carlos Moreira 4.2 Re-election of John O'Hara 4.3 Re-election of Peter Ward 4.4 Re-election of Philippe Doubre 4.5 Re-election of David Fergusson 4.6 Re-election of Jean-Philippe Ladisa 4.7 Re-election of Philippe Monnier In addition, the Board of Directors proposes the election of Andrew Forson as a new member of the Board of Directors for a term extending until completion of the next Annual General Meeting 4.8 Election of Andrew Forson Item 5 Re-election of the Chairman of the Board of Directors for a Term Extending Until Completion of the Next Annual General Meeting Item 6 Re-election of Three Members of the Nomination & Compensation Committee, Each for a Term Extending Until Completion of the Next Annual General Meeting 6.1 Re-election of David Fergusson 6.2 Re-election of Jean-Philippe Ladisa 6.3 Re-election of Philippe Doubre Item 7 Re-election of BDO SA, Vernier, as the Company's Auditor for a Further One-Year Term Item 8 Re-election of the Independent Proxy for a Term Extending Until Completion of the Next Annual General Meeting Item 9 Advisory Vote on the Company's Compensation Report for Fiscal Year 2025 Item 10 Vote on the Compensation of the Board of Directors and the Executive Management Item 10.1 Ratification of the Maximum Aggregate Amount of Compensation of the Board of Directors for the Period Between the 2026 Annual General Meeting and the 2027 Annual General Meeting Item 10.2 Ratification of the Maximum Aggregate Amount of Compensation of the Executive Management for Fiscal Year 2027 Item 10.3 Ratification of Increase in the Max Aggregate Amount of Compensation for the Executive Management for Fiscal Year 2026 Item 10.4 Ratification of Additional Compensation of CHF 1,530,301 to be Granted to the Executive Management in the Form of Options Relating to SEALSQ Ordinary Shares for Fiscal Year 2025 With regard to any modified agenda items, proposals or other matters for which voting is permissible under Swiss law and which are properly presented at the Annual General Meeting, I hereby authorize the Independent Proxy to proceed as follows: to vote in favor of any proposal of the Board of Directors to vote against any proposal to abstain

Exhibit 99.3

Dear valued ADR holder,

We herewith inform you that the 2026 Annual General Meeting (the “AGM”) of the Shareholders of WISeKey International Holding Ltd (the “Company”) will be held on June 29, 2026, and that all ADR holders as of the close of business on May 21, 2026 will be entitled to vote.

For environmental reasons, the Company has decided to reduce the amount of paper used for this mailing to the extent possible. As a result, you are only receiving this brief Notice accompanied by the voting instruction card.

The invitation which includes the agenda with the explanatory notes is available at the Company’s website at URL: https://www.wisekey.com/company/investors/

If you would like to obtain a printed copy of the invitation which includes the agenda with explanatory notes to the AGM, please write to:

BetaNXT, Inc.

Attn: WISEKey International Holding Ltd – 2026 AGM

P.O. Box 8016

Cary, NC 27512-9903

or please call the following number: 1-800-555-2470.

Exhibit 99.4

Copyright © 2026 BetaNXT, Inc. or its affiliates. All Rights Reserved styleIPC Instructions to The Bank of New York, as Depositary (Must be received prior to 12:00 P.M. Eastern Standard Time on June 25, 2026) The undersigned registered holder of American Depositary Receipts ("Receipts") hereby requests and instructs The Bank of New York, as Depositary, to endeavor, insofar as practicable, to vote or cause to be voted the amount of Shares or other Deposited Securities represented by the American Depositary Shares evidenced by such Receipt(s) of WISeKey International Holding Ltd, registered in the name of the undersigned on the books of the Depositary as of the close of business on May 21, 2026 at the Annual General Meeting of WISeKey International Holding Ltd to be held on June 29, 2026, in respect of the resolutions specified on the reverse herein. NOTE: 1. Instructions as to voting on the specific resolutions should be indicated by an (X) in the appropriate box. 2. The Depositary shall not vote or attempt to exercise the right to vote that attaches to the deposited Shares other than in accordance with instructions given by Owners and received by the Depositary or as provided in the following sentence. If (i) no instructions are received by the Depositary from an Owner with respect to a matter and an amount of American Depositary Shares of that Owner on or before May 21, 2026 and (ii) the Depositary has received from the Company, by June 25, 2026, a written confirmation that (x) the Company wishes a proxy to be given under the Deposit Agreement, (y) the Company reasonably does not know of any substantial opposition to the matter and (z) the matter is not materially adverse to the interests of shareholders, then, the Depositary shall deem that Owner to have instructed the Depositary to vote or cause to be voted, and the Depositary shall vote or cause to be voted upon such instructions, that amount of deposited Shares as to that matter in accordance with the recommendations of the Company's Board of Directors. WISeKey International Holding Ltd PLEASE BE SURE TO SIGN AND DATE THIS PROXY CARD AND MARK ON THE REVERSE SIDE WISeKey International Holdings S.A. Annual General Meeting of Shareholders For Shareholders of record as of May 21, 2026 Monday, June 29, 2026 2:00 PM (Switzerland time zone) BNY: PO BOX 505006, Louisville, KY 40233-5006 Mail: • Mark, sign and date your Proxy Card • Fold and return your Proxy Card in the postage-paid envelope provided YOUR VOTE IS IMPORTANT! PLEASE VOTE BY: 12:00 P.M. Eastern Standard Time June 25, 2026 Have your ballot ready and please use one of the methods below for easy voting: Your vote matters! Your control number Have the 12 digit control number located in the box above available when you access the website and follow the instructions.

Please mark vote as indicated in this example X PROPOSAL0 YOUR VOTE FOR AGAINST ABSTAIN 1. Approval of the Annual Report 2025 of WISeKey International Holding Ltd, Including the Audited Consolidated Financial Statements for Fiscal Year 2025 and the Audited Statutory Financial Statements for Fiscal Year 2025 #P1# #P1# #P1# 2. Discharge of the Members of the Board of Directors and the Executive Management from Liability for Activities During Fiscal Year 2025 #P2# #P2# #P2# 3. Appropriation of Accumulated Loss for Fiscal Year 2025 #P3# #P3# #P3# 4. Re-election of 7 Members of the Board of Directors and Election of 1 New Member of the Board of Directors, All for a Term Extending Until Completion of the Next Annual General Meeting Re-election of Carlos Moreira #P5# #P5# #P5# Re-election of John O'Hara #P6# #P6# #P6# Re-election of Peter Ward #P7# #P7# #P7# Re-election of Philippe Doubre #P8# #P8# #P8# Re-election of David Fergusson #P9# #P9# #P9# Re-election of Jean-Philippe Ladisa #P10# #P10# #P10# Re-election of Philippe Monnier #P11# #P11# #P11# In addition, the Board of Directors proposes the election of Andrew Forson as a new member of the Board of Directors for a term extending until completion of the next Annual General Meeting: Election of Andrew Forson #P13# #P13# #P13# 5. Re-election of the Chairman of the Board of Directors for a Term Extending Until Completion of the Next Annual General Meeting #P14# #P14# #P14# 6. Re-election of Three Members of the Nomination & Compensation Committee, each for a Term Extending Until Completion of the Next Annual General Meeting Re-election of David Fergusson #P16# #P16# #P16# Re-election of Jean-Philippe Ladisa #P17# #P17# #P17# Re-election of Philippe Doubre #P18# #P18# #P18# 7. Re-election of BDO SA, Vernier, as the Company's Auditor for a Further One-Year Term #P19# #P19# #P19# 8. Re-election of the Independent Proxy for a Term Extending Until Completion of the Next Annual General Meeting #P20# #P20# #P20# 9. Advisory Vote on the Company's Compensation Report for Fiscal Year 2025 #P21# #P21# #P21# PROPOSAL20 YOUR VOTE 10. Vote on the Compensation of the Board of Directors and the Executive Management FOR AGAINST ABSTAIN 10.1 Ratification of the Maximum Aggregate Amount of Compensation of the Board of Directors for the Period Between the 2026 Annual General Meeting and the 2027 Annual General Meeting #P23# #P23# #P23# 10.2 Ratification of the Maximum Aggregate Amount of Compensation of the Executive Management for Fiscal Year 2027 #P24# #P24# #P24# 10.3 Ratification of Increase in the Max Aggregate Amount of Compensation for the Executive Management for Fiscal Year 2026 #P25# #P25# #P25# 10.4 Ratification of Additional Compensation of CHF 1,530,301 to be Granted to the Executive Management in the Form of Options Relating to SEALSQ Ordinary Shares for Fiscal Year 2025 #P26# #P26# #P26# Proposal_Page - VIFS Authorized Signatures - Must be completed for your instructions to be executed. Please sign exactly as your name(s) appears on your account. If held in joint tenancy, all persons should sign. Trustees, administrators, etc., should include title and authority. Corporations should provide full name of corporation and title of authorized officer signing the Proxy/Vote Form. Signature (and Title if applicable) Date Date Signature (if held jointly)