Profusa Inc美股招股说明书(2026-02-10版)

2,962,962 Shares of Common Stock by the Selling Stockholder This prospectus supplement amends and supplements certain information contained in the prospectus dated September 26,2025 (the “Prospectus”), which forms a part of our registration statement on Form S-1, as amended (File No. 333-289958). TheProspectus and this prospectus supplement relate to the offer and resale from time to time, of up to 2,962,962 shares of our CommonStock, par value $0.0001 per share (“the Common Stock”), issuable upon conversion of certain convertible promissory notes (the“Ascent Notes,” and upon conversion the “Conversion Shares”), with an aggregate principal value of $22,222,222 by Ascent PartnersFund LLC (the “Selling Stockholder”). The Common Stock being offered for resale consists of up to 2,962,962Conversion Sharespursuant to the securities purchase agreement, dated as of February 11, 2025, we entered into with the Selling Stockholder (the “PIPESubscription Agreement”). There is no guarantee that the Ascent Note (or the full note amount thereof) will be converted into shares ofCommon Stock. The Ascent Note may not be converted by Ascent into shares of Common Stock if such conversion would result in theinvestors or their affiliates owning in excess of 4.99% of the number of shares of Common Stock outstanding immediately after givingeffect to the issuance of all shares issuable upon conversion of the Ascent Note (the “Beneficial Ownership Limitation”); provided,that Ascent may increase or decrease the Beneficial Ownership Limitation upon at least 61days’ prior notice to us so long as suchincrease does not exceed 9.99% of the number of shares of Common Stock outstanding immediately after giving effect to the issuanceof all shares issuable upon conversion of the Ascent Note. On August1, pursuant to a Notice and Waiver, the Beneficial OwnershipLimitation was increased from 4.99% to 9.99% and we waived the requirement for the 60 days’ advance notice for such increase. We will not receive any of the proceeds from the sale of Common Stock by the Selling Stockholder. The Selling Stockholder may sell the shares of our common stock offered by the Prospectus and this prospectus supplementfrom time to time on terms to be determined at the time of sale through ordinary brokerage transactions or through any other means.The shares of common stock may be sold at fixed prices, at market prices prevailing at the time of sale, at prices related to prevailingmarket price or at negotiated prices. This prospectus supplement is being filed to update and supplement the information in the Prospectus with the informationcontained in our Current Report on Form 8-K, filed with the SEC on September 16, 2025 (the “September Current Report”) and ourCurrent Report on Form 8-K, filed with the SEC on February 5, 2026 (the “February Current Report”). Accordingly, we have attachedthe September Current Report and February Current Report to this prospectus supplement. On February 9, 2026, we effected a reverse stock split at a ratio of 1-for-75 (the “Reverse Stock Split”), which is more fullydescribed in this prospectus supplement. Unless the context otherwise requires, all share numbers, exercise prices, conversion pricesand other share data in this prospectus supplement have been adjusted to give effect to the Reverse Stock Split. Our common stock is listed on the Nasdaq Global Market under the symbol “PFSA.” On February 9, 2025, the last sale pricefor our common stock as reported on the Nasdaq Global Market was $3.16 per share. This prospectus supplement should be read in conjunction with the Prospectus, including any amendments or supplementsthereto, which is to be delivered with this prospectus supplement. This prospectus supplement is qualified by reference to theProspectus, including any amendments or supplements thereto, except to the extent that the information in this prospectus supplementupdates and supersedes the information contained therein. This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, theProspectus, including any amendments or supplements thereto. We are a “smaller reporting company” as defined under the federal securities laws and, as such, have elected to comply withcertain reduced public company reporting requirements for the Prospectus and this prospectus supplement and may elect to do so infuture filings. We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012 (“JOBS Act”). As aresult, we are eligible to take advantage of certain reduced disclosure and other requirements that are otherwise applicable to publiccompanies. See further discussion below. Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertaintiesdescribed under the heading“Risk Factors”section of the Prospectus, and under similar headings in any amendment orsupplements thereto, and in our most recent