PDF Solutions Inc美股招股说明书(2026-05-13版)

Common Stock We are offering 500,000 shares of our common stock and the selling stockholder identified in this prospectus supplement(the “selling stockholder”) is offering 3,306,924 shares of our common stock. We will not receive any of the proceeds from the saleof shares of our common stock by the selling stockholder. We have granted the underwriters the option to purchase up to an additional 571,038 shares of common stock at the publicoffering price, less underwriting discounts and commissions, within 30 days from the date of this prospectus supplement. Our common stock is listed on the Nasdaq Global Select Market (the “Nasdaq”) under the symbol “PDFS.” On May12,2026, the last reported sale price of our common stock on Nasdaq was $50.95 per share. Investing in our common stock involves risks. See “Risk Factors” beginning on pageS-20 of thisprospectus supplement and page S-4 of the accompanying prospectus, as well as the documentsincorporated by reference in this prospectus supplement, before making a decision to invest in our commonstock. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or passed upon the adequacy or accuracy of this prospectus supplement and accompanying prospectus. Anyrepresentation to the contrary is a criminal offense. PerShareTotalPublic offering price$$Underwriting discounts and commissions (1)$$Proceeds, before offering expenses, to us$$Proceeds, before offering expenses, to the selling stockholder$$ (1)See the section titled “Underwriting (Conflict of Interest)” for additional information regarding compensation payable to theunderwriters. The underwriters expect to deliver the shares of common stock to purchasers on or about May, 2026. Needham& Company Table of Contents TABLE OF CONTENTSPROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTNON-GAAP FINANCIAL MEASURESSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGSUMMARY HISTORICAL CONSOLIDATED FINANCIAL INFORMATIONRISK FACTORSUSE OF PROCEEDSCAPITALIZATIONSELLING STOCKHOLDERMATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERSUNDERWRITING (CONFLICT OF INTEREST)LEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE PROSPECTUS ABOUT THIS PROSPECTUSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSWHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCETHE COMPANYRISK FACTORSUSE OF PROCEEDSDESCRIPTION OF CAPITAL STOCK SELLING SECURITYHOLDERS PLAN OF DISTRIBUTION LEGAL MATTERS EXPERTS We, the selling stockholder and the underwriters have not authorized anyone to provide any information or to make any representations other thanthose contained in this prospectus supplement or in any free writing prospectuses we have prepared or that have been prepared on our behalf or to whichwe have referred you. We, the selling stockholder and the underwriters take no responsibility for, and can provide no assurance as to the reliability of,any other information that others may give you. We, the selling stockholder and the underwriters are offering to sell, and seeking offers to buy, shares ofcommon stock only in jurisdictions where offers and sales are permitted. The information contained in this prospectus supplement is accurate only as ofthe date of this prospectus supplement, regardless of the time of delivery of this prospectus supplement or of any sale of the common stock. For investors outside the United States: We, the selling stockholder and the underwriters have not done anything that would permit this offering orpossession or distribution of this prospectus supplement in any jurisdiction where action for that purpose is required, other than in the United States.Persons outside of the United States who come into possession of this prospectus supplement must inform themselves about, and observe anyrestrictions relating to, the offering of the shares of common stock and the distribution of this prospectus supplement outside of the United States. Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT As used in this prospectus supplement and the accompanying prospectus, the terms “PDF Solutions,” “PDF,” the “Company,” “we,” “us” and“our” refer to PDF Solutions, Inc., and its consolidated subsidiaries, unless otherwise specified. This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of shares of commonstock and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference into thisprospectus supplement and the accompanying prospectus. The second part is the accompanying prospectus, which gives more general information, someof which may not apply to this offering of shares of common stock. Generally, when we refer to this prospectus supplement, we are referring to bothparts of this document combined. In this prospectus suppleme