<div id="readability-page-1"><article>Geneva, Switzerland, December 22, 2025 – WISeKey International Holding Ltd (“WISeKey”) (SIX: WIHN, NASDAQ: WKEY), a leading global cybersecurity, blockchain, and IoT company, today issued a Letter to Shareholders by its Founder and CEO, Carlos Moreira. Dear Shareholders, <img src="https://imageproxy.pbkrs.com/https://ml-eu.globenewswire.com/Resource/Download/50f9a810-4f8c-4238-96de-bb67a5150f4e/image2.png?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" width="798" height="449" original-src="https://imageproxy.pbkrs.com/https://ml-eu.globenewswire.com/Resource/Download/50f9a810-4f8c-4238-96de-bb67a5150f4e/image2.png"/> As we close 2025, I would like to take a moment to reflect on what has been an exceptional year for the WISeKey Group of Companies. 2025 marked a significant milestone year in the execution of WISeKey’s long-term strategy as a technology holding company and innovation platform, with a mission to create a secure, connected, and quantum-resilient future. Our proven model, successfully demonstrated by the 2023 listing on Nasdaq of our Semiconductors, PKI, and Post-Quantum technology subsidiary, SEALSQ’s Corp (NASDAQ: LAES) (&#34;SEALSQ&#34;), which continued to gain strong market validation in 2025 via its uplisting on NASDAQ Global Select tier, being recognized as one of the fastest-growing technology companies in the emerging quantum era. This momentum for WISeKey was further reinforced by several milestones at our subsidiaries, including: <ul type="disc"><li>The strategic acquisition of IC’ALPS in mid-2025: The acquisition of IC’ALPS, a leading ASIC design company, added 100 highly skilled engineers and experts to the Group, brought WISeKey’s total workforce to approximately 300 employees worldwide and significantly strengthened its semiconductor design and innovation capabilities.</li><li>The launch of a $100 million Quantum Fund in mid-2025: The Quantum Fund is accelerating innovation across the quantum ecosystem, with initial investments already completed in promising startups such as ColibryTD and EeroQ.</li><li>The commercial launch of our Quantum Shield QS7001™ and QVault™ TPM solutions: The launch, strategically positions WISeKey at the forefront of the digital trust revolution and marks the start of a clear and sustained growth phase for WISeKey, is backed by the establishment of European Personalization Centers and our global leadership in post-quantum cryptography and space connectivity, we are. </li><li>The upcoming listing of WISeSat, via a merger with a SPAC: The merger, which is expected to be completed in the first half of 2026, aims to accelerate the commercialization of our satellite-based cybersecurity and IoT ecosystem and enabling WISeSat to emerge as a new, independent publicly listed space-tech company on Nasdaq. Our satellite constellation is purpose-built to deliver trusted IoT connectivity from space, secured by SEALSQ post-quantum cryptographic chips and anchored in the WISeKey Root of Trust.</li><li>SEALCOIN’s preparations for the launch of the QAIT Token in Q1 2026: The primary function of the QAIT Token is to facilitate decentralized payments and validate communication between IoT devices and AI agents on the SEALCOIN platform. It is central to building a &#34;transactional Internet of Things&#34; where devices can autonomously interact and pay for services. </li></ul> These strategic initiatives are underpinned by a very strong balance sheet supported by cash position of over $440 million as of December 19, 2025, providing WISeKey with exceptional financial flexibility to execute its growth strategy, pursue selective acquisitions, and invest in breakthrough technologies. Our Vision WISeKey has now entered its ‘Year of Convergence’ by bringing together four foundational pillars: semiconductors, satellites, blockchain, and digital identity, into unified and interoperable ecosystems. This convergence allows us to offer end-to-end solutions where each component reinforces the other, enabling exponential innovation and resilience. By integrating semiconductors, trust services, satellites, blockchain, digital identity, and certified digital assets into a unified architecture of trust, WISeKey is no longer operating isolated businesses, but a single, interconnected ecosystem. A clear example of this Convergence was announced on October 1, 2025, with the introduction of a new suite of solutions designed to protect AI operations and decision-making processes against adversarial quantum attacks. This breakthrough builds on SEALSQ’s pioneering expertise in post-quantum cryptography and trusted semiconductor technologies, combined with SEALCOIN’s verifiable identity, decentralized execution, and post-quantum-resilient blockchain infrastructure. Operating as a technology holding company and innovation platform, leveraging a disciplined and repeatable strategy across its portfolio of subsidiary companies, each entity within the WISeKey ecosystem follows a structured growth pathway, from incubation and technological validation to market expansion and, ultimately, public listing. This approach enables WISeKey to unlock the intrinsic value of its innovations, attract strategic investors, and maximize shareholder returns. By methodically preparing and listing subsidiaries across cybersecurity, semiconductors, space technology, blockchain, digital identity, and now certified digital assets, WISeKey is building a resilient and diversified technology group that supports long-term value creation and global leadership in trusted digital ecosystems. Specifically… <ul type="disc"><li>SEALSQ, which is at the heart of WISeKey’s convergence strategy, develops post-quantum secure chips such as the QS7001™ and QVault™ TPM. These technologies are engineered for mission-critical sectors including defense, IoT, satellites, automotive, smart cities, and AI systems, providing robust protection against “harvest-now, decrypt-later” threats. They are designed to generate both one-time hardware revenues and recurring income through chip personalization services delivered via Outsourced Semiconductor Personalization and Test centers. </li><li>Designed for interoperability, these secure chips connect directly with the WISeSat.Space satellite constellation, including the 23rd satellite scheduled for launch in November 2025, while SEALCOIN enables autonomous, chip-level transactions that unlock transaction-based revenue across the machine-to-machine and transactional IoT economy.</li><li>Complementing this ecosystem, the WISeID platform provides the PKI infrastructure securing digital identities, devices, and transactions, supporting applications such as Matter Protocol certification for smart home devices and GSMA eUICC digital identity services. </li><li>Preparing for 2026, the WISe.ARt platform is expanding beyond the art world to enable certified digital assets and digital twins for the luxury sector and a broad range of real-world and digital assets, leveraging WISeKey’s trust, identity, and blockchain technologies to bring authenticity, traceability, and value preservation to new markets.</li></ul> Expanding Global Footprint Through SEALSQ, WISeKey has also expanded its Quantum Corridor initiative with projects in India, the United Arab Emirates, and Brazil, strengthening regional post-quantum cryptography infrastructure and supporting the development of sovereign semiconductor ecosystems. These initiatives reflect WISeKey’s commitment to building a globally integrated post-quantum ecosystem connecting Europe, Asia, the Middle East, and Latin America through trusted semiconductor innovation and secure digital infrastructure. Our progress is further reinforced by strategic initiatives such as the Quantix Edge Security project in Spain, positioning WISeKey at the heart of Europe’s semiconductor sovereignty strategy; collaboration with the Swiss Army, integrating WISeSat, SEALSQ, and SEALCOIN technologies into a single sovereign communications framework; and the HUMAN-AI-T initiative with the United Nations, which places WISeKey at the forefront of global AI governance and reinforces our leadership at the intersection of AI, security, and trust. Redomiciliation to the British Virgin Islands The recently announced plan to change our jurisdiction of incorporation from Switzerland to the British Virgin Islands is expected to provide WISeKey with enhanced strategic and operational flexibility. This transition is intended to improve access to equity capital markets in both the United States and Switzerland and to support future strategic acquisitions. Upon completion of the redomiciliation, WISeKey expects its ordinary shares to be primarily listed on Nasdaq, with a secondary listing on the SIX Swiss Exchange, continuing WISeKey Switzerland’s current presence on SIX. We are entering 2026, with strong momentum, expanded capabilities, a growing global team, a solid financial foundation, and an increasingly broad portfolio of trusted digital services. As the quantum era rapidly approaches, WISeKey continues to innovate and expand its solutions, ensuring that organizations, governments, and individuals can operate with confidence in an increasingly complex technological landscape. We are confident that our strategic initiatives and technological advancements will drive sustainable growth and reinforce our leadership within the global cybersecurity and digital trust ecosystem. On behalf of our entire management team and board of directors, I would like to sincerely thank our employees, partners, customers, and shareholders for their trust, commitment, and continued support. We wish you all happy holidays and a prosperous 2026. Regards Carlos Moreira Founder and CEO About WISeKey <div>WISeKey International Holding Ltd (“WISeKey”, SIX: WIHN; Nasdaq: WKEY) is a global leader in cybersecurity, digital identity, and IoT solutions platform. It operates as a Swiss-based holding company through several operational subsidiaries, each dedicated to specific aspects of its technology portfolio. The subsidiaries include (i) SEALSQ Corp (Nasdaq: LAES), which focuses on semiconductors, PKI, and post-quantum technology products, (ii) WISeKey SA which specializes in RoT and PKI solutions for secure authentication and identification in IoT, Blockchain, and AI, (iii) WISeSat AG which focuses on space technology for secure satellite communication, specifically for IoT applications, (iv) WISe.ART Corp which focuses on trusted blockchain NFTs and operates the WISe.ART marketplace for secure NFT transactions, and (v) SEALCOIN AG which focuses on decentralized physical internet with DePIN technology and house the development of the SEALCOIN platform.Each subsidiary contributes to WISeKey’s mission of securing the internet while focusing on their respective areas of research and expertise. Their technologies seamlessly integrate into the comprehensive WISeKey platform. WISeKey secures digital identity ecosystems for individuals and objects using Blockchain, AI, and IoT technologies. With over 1.6 billion microchips deployed across various IoT sectors, WISeKey plays a vital role in securing the Internet of Everything. The company’s semiconductors generate valuable Big Data that, when analyzed with AI, enable predictive equipment failure prevention. Trusted by the OISTE/WISeKey cryptographic Root of Trust, WISeKey provides secure authentication and identification for IoT, Blockchain, and AI applications. The WISeKey Root of Trust ensures the integrity of online transactions between objects and people. For more information on WISeKey’s strategic direction and its subsidiary companies, please visit www.wisekey.com.</div> Disclaimer This communication expressly or implicitly contains certain forward-looking statements concerning WISeKey International Holding Ltd and its business. Such statements involve certain known and unknown risks, uncertainties and other factors, which could cause the actual results, financial condition, performance or achievements of WISeKey International Holding Ltd to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. WISeKey International Holding Ltd is providing this communication as of this date and does not undertake to update any forward-looking statements contained herein as a result of new information, future events or otherwise. <div>This press release does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, and it does not constitute an offering prospectus within the meaning of the Swiss Financial Services Act (“FinSA”), the FinSa's predecessor legislation or advertising within the meaning of the FinSA. Investors must rely on their own evaluation of WISeKey and its securities, including the merits and risks involved. Nothing contained herein is, or shall be relied on as, a promise or representation as to the future performance of WISeKey.Press and Investor Contacts</div> <table><tbody><tr><td>WISeKey International Holding Ltd Company Contact: Carlos Moreira Chairman &amp; CEO Tel: +41 22 594 3000 info@wisekey.com </td><td>WISeKey Investor Relations (US) The Equity Group Inc. Lena Cati Tel: +1 212 836-9611 lcati@theequitygroup.com </td></tr></tbody></table><img src="https://imageproxy.pbkrs.com/https://www.globenewswire.com/newsroom/ti/query-bmY9TVRBd01URTFOakV5T1NNME1ESXpNRFk0TlRRak1qQXdNelU1Tnc9PQ?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" width="1" height="1" original-src="https://imageproxy.pbkrs.com/https://www.globenewswire.com/newsroom/ti/query-bmY9TVRBd01URTFOakV5T1NNME1ESXpNRFk0TlRRak1qQXdNelU1Tnc9PQ"/> <img src="https://imageproxy.pbkrs.com/https://ml-eu.globenewswire.com/media/ZjIzMTM2MjctYzZkMC00NDc0LWEyYTQtNmNlYmJhNGMwMzU2LTEwMTUxNzAtMjAyNS0xMi0yMi1lbg==/tiny/Wisekey-International-Holding-.png?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" width="1" height="1" original-src="https://imageproxy.pbkrs.com/https://ml-eu.globenewswire.com/media/ZjIzMTM2MjctYzZkMC00NDc0LWEyYTQtNmNlYmJhNGMwMzU2LTEwMTUxNzAtMjAyNS0xMi0yMi1lbg==/tiny/Wisekey-International-Holding-.png"/></article></div>

WKEY

WISeKey's CEO, Carlos Moreira, issued a year-end letter to shareholders highlighting 2025 milestones, including strategic acquisitions, product launches, and financial strength. Key achievements include acquiring IC’ALPS, launching a $100 million Quantum Fund, and preparing for WISeSat's SPAC merger. WISeKey aims to converge semiconductors, satellites, blockchain, and digital identity into a unified ecosystem, enhancing innovation and resilience. The company boasts a strong balance sheet with over $440 million in cash, supporting its growth strategy and technological investments.

WISeKey Issues Year-End CEO Letter to Shareholders | WKEY Stock News