Geneva, Switzerland, March 16, 2026 -- SEALSQ Corp ("SEALSQ" or "Company"), a company that focuses on developing and selling Semiconductors, PKI and Post-Quantum technology hardware and software products, today announced that it has entered into a securities purchase agreement with several institutional investors to purchase 30,413,630 ordinary shares (or pre-funded warrants in lieu thereof) and accompanying warrants to purchase up to 60,827,260 ordinary shares priced at-the-market under Nasdaq rules (the “Offering”). The combined purchase price per ordinary share (or pre-funded warrant) and accompanying warrants was $4.11. The warrants will have an exercise price of $5.50 per ordinary share, will be immediately exercisable, and will expire seven years following the date of issuance. Gross proceeds for the Offering are expected to be approximately $125.0 million, before deducting commissions and offering expenses. The Offering will be led by an affiliate of Heights Capital Management, Inc.

Maxim Group LLC is acting as the sole placement agent for the Offering.

SEALSQ currently intends to utilize the net proceeds from the Offering to reinforce its already strong cash position, allowing the company to accelerate its Post-Quantum and Quantum commercialization roadmap and deployment in the United States and in Europe. The Offering is expected to close on or about March 17, 2026, subject to the satisfaction of customary closing conditions.

The Offering is being made pursuant to an effective shelf registration statement on Form S-3ASR (File No. 333-290963), which was filed with the Securities and Exchange Commission (the “SEC“) and was automatically effective upon filing on October 20, 2025. The Offering is being made only by means of a prospectus supplement and accompanying prospectus that form a part of the effective shelf registration statement. A prospectus supplement relating to the securities to be issued in the Offering will be filed by the Company with the SEC. When available, copies of the prospectus supplement relating to the Offering, together with the accompanying prospectus, can be obtained at the SEC's website at www.sec.gov or by contacting Maxim Group LLC, at 300 Park Avenue, 16th Floor, New York, NY 10022, Attention: Syndicate Department, or via email at syndicate@maximgrp.com or by telephone at (212) 895-3745.