闪迪美股招股说明书(2026-02-18版)

The selling stockholders identified in this prospectus supplement are offering 5,821,135shares of our common stock. We will not receive any of the proceeds from the sale of shares of our All of the shares of our common stock that are being offered and sold in this offering are currently held by Western Digital Corporation (“WDC”). Immediately after the completion of thedebt-for-equity exchange, WDC is expected to own 1,691,884shares of our common stock, which it intends to dispose of in one or more subsequent exchanges for outstanding shares of WDCcommon stock and/or through pro rata distributions to WDC stockholders. We are registering the resale of the shares of our common stock to be offered and sold in this offering pursuant tothe terms of a stockholder’s and registration rights agreement between us and WDC (the “SRRA”). In connection with this offering, WDC intends to exchange 5,821,135shares of our common stock offered hereby for certain indebtedness of WDC under (i)that certain Amended andRestated Loan Agreement, dated as of January7, 2022, among WDC, JPMorgan Chase Bank, N.A., as administrative agent, and the lenders party thereto, which governs WDC’s$1.586billion term A-3 loans (“Term A-3 Loans”) and revolving credit facility maturing in January 2027 (the “Existing Credit Facility”), and (ii)that certain Loan Agreement, dated as ofFebruary5, 2026, among WDC, JPMorgan Chase Bank, N.A., as administrative agent, and the lenders party thereto, which governs WDC’s $1.500billion term loans (“Term Loans”)maturing in March 2026 (the “New Credit Facility” and, together with the Existing Credit Facility, the “Credit Facilities”), each of which is held by affiliates of J.P. Morgan Securities LLCand BofA Securities, Inc., as the selling stockholders identified in this prospectus supplement (the “selling stockholders” and, such affiliates, the “debt-for-equity exchange parties”). In thedebt-for-equity exchange, WDC is expected to deliver the shares, at the request of the debt-for-equity exchange parties, to the selling stockholders upon consummation of the debt-for-equityexchange, and the selling stockholders would then offer those shares of our common stock to the underwriters in this offering for cash. The consummation of the debt-for-equity exchange is acondition to the settlement of the selling stockholders’ sale of the shares to the underwriters. As a result, the consummation of the debt-for-equity exchange is also a condition to the settlementof the underwriters’ sale of the shares to prospective investors. The debt-for-equity exchange parties, and not WDC or us, will receive the proceeds from the sale of the shares in this offering.However, as a result of exchanging the shares of our common stock with the debt-for-equity exchange parties prior to this offering, WDC may be deemed to be a selling stockholder in thisoffering solely for U.S. federal securities law purposes. We refer to the exchange between WDC and the debt-for-equity exchange parties as the “debt-for-equity exchange,” which will beeffected pursuant to a debt-for-equity exchange agreement expected to be entered into before the settlement date of this offering. The debt-for-equity exchange will occur on the settlementdate of this offering immediately prior to, and its consummation will be a condition to, the settlement of the selling stockholders’ sale of the shares to the underwriters in this offering. As aresult, the consummation of the debt-for-equity exchange will also ultimately be a condition to the settlement of the underwriters’ sale of the shares to prospective investors in this offering.See “Principal and Selling Stockholders” and “Underwriting (Conflicts of Interest).” Our common stock is listed on the Nasdaq Stock Market LLC (“Nasdaq”) under the symbol “SNDK.” On February17, 2026, the closing price of our common stock as reported on the Nasdaqwas $590.59 per share. Investing in our common stock involves a high degree of risk. Before buying any shares of our common stock, you should carefullyread the discussion of material risks of investing in our common stock in “Risk Factors” beginning on page S-10. Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved these securities or determined if this prospectussupplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense. Public offering price (1)See “Underwriting (Conflict of Interest)” for a description of compensation to be paid to the underwriters. The underwriters are offering the shares of our common stock as set forth under “Underwriting (Conflicts of Interest).” Delivery of the shares of our common stock willbe made on or about February19, 2026. Joint Book-Running Managers J.P. MorganRBC Capital MarketsTruist Securities BTIGPNC Capital Markets LLC SMBC NikkoBarclays Table of Contents TABLE OF CONTENTS Prospectus Supplement PROSPECTUS SUPPLEMENT