Nyxoah SA美股招股说明书(2026-06-08版)

55,232,558 Ordinary Shares We are offering 55,232,558 of our ordinary shares pursuant to this prospectus supplement. Our ordinaryshares are listed on The Nasdaq Global Market under the symbol “NYXH” and on Euronext Brussels under thesymbol “NYXH”. On June 5, 2026, the last reported sale price of our ordinary shares on Nasdaq was $1.45 perordinary share and the last reported sales price of our ordinary shares on Euronext was €2.46 per ordinary share.We have granted the underwriters an option for a period of 30days after the date of this prospectus supplement topurchase up to an additional 8,284,883 of our ordinary shares, at the public offering price less the underwritingdiscount, solely to cover over-allotments. Our business and an investment in our ordinary shares involve significant risks. These risks are described underthe caption “Risks Related to This Offering” beginning on pageS-9of this prospectus supplement under the caption“Risk Factors” and in the documents incorporated by reference into this prospectus supplement and theaccompanying prospectus. Neither the Securities and Exchange Commission nor any state securities commission has approved ordisapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement or theaccompanying prospectus. Any representation to the contrary is a criminal offense. (1)Equivalent to a sale price of €1.48 per ordinary share based on an exchange rate of €1 to $1.16 on June5,2026, as published by the European Central Bank. (2)We refer you to “Underwriting” beginning on pageS-38of this prospectus supplement for additionalinformation regarding underwriting compensation. Certain of our existing stockholders, who are directors or affiliated with certain of our directors, haveindicated an interest in purchasing an aggregate of 13,712,900 ordinary shares in this offering at the publicoffering price. However, because their indications of interest are not binding agreements or commitments topurchase, the underwriters may sell more, less or no securities in this offering to any or all of these persons, orany or all of these persons may determine to purchase more, less or no securities in this offering. The underwriterswill receive the same underwriting discount on any securities purchased by these stockholders as they will on anyother securities sold to the public in this offering. Delivery of the ordinary shares is expected to be made on or about June 9, 2026, which is the secondbusiness day following the initial trade date for our ordinary shares (this settlement cycle being referred to as“T+2”). Under Rule15c6-1 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), tradesin the secondary market generally are required to settle in one business day, unless the parties to any such tradeexpressly agree otherwise. Accordingly, purchasers who wish to trade our ordinary shares prior to the businessday preceding the settlement date will be required, by virtue of the fact that the ordinary shares will initially settleT+2, to specify an alternate settlement cycle at the time of any such trade to prevent a failed settlement.Purchasers of our ordinary shares who wish to trade the shares prior to the business day preceding the settlementdate should consult their own advisors. Book-running Managers BofA Securities Degroof Petercam Co-manager B. Riley Securities The date of this prospectus supplement is June 5, 2026. TABLE OF CONTENTS PROSPECT SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTS-1PRESENTATION OF FINANCIAL INFORMATIONS-2PROSPECTUS SUPPLEMENT SUMMARYS-3THE OFFERINGS-7RISK FACTORSS-9SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSS-15USE OF PROCEEDSS-17CAPITALIZATIONS-18DILUTIONS-19MATERIAL UNITED STATES FEDERAL INCOME AND BELGIAN TAX CONSIDERATIONSS-20UNDERWRITING.S-38LEGAL MATTERSS-46EXPERTSS-46ENFORCEMENT OF JUDGMENTSS-46WHERE YOU CAN FIND MORE INFORMATIONS-48INCORPORATION OF DOCUMENTS BY REFERENCES-49PROSPECTUSABOUT THIS PROSPECTUS1PROSPECTUS SUMMARY2RISK FACTORS4SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS5CAPITALIZATION8USE OF PROCEEDS9PLAN OF DISTRIBUTION10DESCRIPTION OF SHARE CAPITAL12DESCRIPTION OF DEBT SECURITIES27DESCRIPTION OF WARRANTS33DESCRIPTION OF RIGHTS34DESCRIPTION OF UNITS36EXPENSES37LEGAL MATTERS38EXPERTS38ENFORCEMENT OF LIABILITIES39WHERE YOU CAN FIND MORE INFORMATION41INCORPORATION OF DOCUMENTS BY REFERENCE42 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of a registration statement thatwe filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process onMarch20, 2025 and declared effective by the SEC on April1, 2025. Before buying any of the ordinary shares that we are offering, we urge you to carefully read thisprospectus supplement and accompanying prospectus and all of the information incorporated by referenceherein and therein, as well as the additional information described under the headin