Profusa, Inc.

As filed with the Securities and Exchange Commission on August 29, 2025.

Registration No. 333-________

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

626 Bancroft Way

Suite A

Berkeley, CA 94710

(925) 997-6925

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Ben C. Hwang

Chief Executive Officer

626 Bancroft Way

Suite A

Berkeley, CA 94710

(925) 997-6925

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Ralph V. De Martino, Esq.

Marc Rivera, Esq.

ArentFox Schiff LLP

1717 K Street, NW

Washington, DC 20006

Phone: (202) 724-6847

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box:☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. The selling stockholder may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell, nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED August 29, 2025.

PRELIMINARY PROSPECTUS

222,222,222 Shares of Common Stock by the Selling Stockholder

This prospectus relates to the resale, from time to time, by Ascent Partners Fund LLC (“Ascent” or the “Selling Stockholder”) of up to 222,222,222 shares of our Common Stock issuable upon conversion of certain convertible promissory notes, with an aggregate principal value of $22,222,222 (the “Ascent Notes,” and upon conversion, the “Conversion Shares”).

The shares of Common Stock to which this prospectus relates have been or may be issued by us to Ascent pursuant to a securities purchase agreement, dated as of February 11, 2025, we entered into with Ascent, which we refer to in this prospectus as the PIPE Subscription Agreement. There is no guarantee that the Ascent Note (or the full note amount thereof) will be converted into shares of Common Stock. The Ascent Note may not be converted by Ascent into shares of Common Stock if such conversion would result in the investors or their affiliates owning in excess of 4.99% of the number of shares of Common Stock outstanding immediately after giving effect 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 61 days’ prior notice to Profusa so long as such increase does not exceed 9.99% of the number of shares of Common Stock outstanding immediately after giving effect to the issuance of all shares issuable upon conversion of the Ascent Note. On August 1, pursuant to a Notice and Waiver, the Beneficial Ownership Limitation was increased from 4.99% to 9.99% and we waived the requirement for the 60 days’ advance notice for such increase.

The Ascent Note matures on January 11, 2027, which is 18-months from closing of the Company’s business combination on July 11, 2025 (the “Maturity Date”) and is convertible at any time at Ascent’s option at a conversion price equal to the lower of $10 or 95% of the lowest daily volume-weighted average price per share (“VWAP”) of our Common Stock in the 10 trading days prior to the original issue date of the Ascent Note and shall be adjusted, without limitation, based on down-round and most-favored nation (MFN) price and terms protections (the “Conversion Price”).

The Ascent Note includes a “Minimum Interest Amount” equal to 10% of the principal amount, which represents a full year of interest payments under the Ascent Note; provided, that such Minimum Interest Amount shall be reduced by the amount of interest accrued on the principal amount of the Ascent Note. Interest shall accrue on the aggregate unconverted and then outstanding principal amount of the Ascent Note at a rate of 10% per annum, provided that the Minimum Interest Amount shall be fully earned and accrued on the original issue date of the Ascent Note. Upon an event of default, the interest rate shall be adjusted and increase to 24% per annum. Payments made in cash under the Ascent Note shall be subject to a 5% fee, which shall be in addition to any amounts owed thereunder.

On August 25, 2025, the Company entered into Amendment No. 1 (the “SPA Amendment”) to the PIPE Subscription Agreement. Pursuant to the SPA Amendment, Section 2.1 of the PIPE Subscription Agreement was amended and restated to provide for four tranches of Notes: (i) an initial closing for Notes in an aggregate principal amount of $10,000,000 (the “First Tranche”), which already occurred in July 11, 2025; (ii) a second closing for Notes in an aggregate principal amount of $2,222,222 (the “Second Tranche”) for a purchase price of $2,000,000, subject to the satisfaction of certain conditions including the filing of a registration statement on Form S-1 covering all conversion shares and no Nasdaq listing deficiency; (iii) a third closing for Notes in an aggregate principal amount of $5,555,556 (the “Third Tranche”) for a purchase price of $5,000,000, subject to the satisfaction of certain conditions including the full conversion or repayment of the First Tranche, effectiveness of a registration statement, no Nasdaq listing deficiency, and receipt of stockholder approval; and (iv) a fourth closing for Notes in an aggregate principal amount of $4,444,444 (the “Fourth Tranche”) for a purchase price of $4,000,000, subject to the satisfaction of certain conditions including the full repayment of the First and Second Tranches, at least fifty percent (50%) repayment or conversion of the Third Tranche, effectiveness of a registration statement, and no Nasdaq listing deficiency. The Amendment supersedes and replaces all prior provisions relating to “Additional Closings” and “Additional Notes,” and all references to such terms in the PIPE Subscription Agreement and related documents are to be construed in accordance with the new tranche structure.

Simultaneously, on August 25, 2025, the Company entered into Amendment No. 1 (the “Note Amendment”) to the Initial Note. The Note Amendment modifies the terms of the Initial Note, specifically amending Section 4(b) to revise the conversion price provisions on any conversion date to be the lower of (i) the Conversion Price on such date and (ii) ninety-five percent (95%) of the lowest daily volume weighted average price (“VWAP”) for the Company’s common stock during the ten consecutive trading days immediately preceding the applicable conversion date (the “Alternate Conversion Price”), provided that in no event shall the conversion price be less than the Floor Price of twenty percent (20%) of the closing sale price of the common stock on the principal trading market on the trading day immediately preceding the Note Amendment’s effective date, which was August 22, 2025.

We are not selling any securities under this prospectus and will not receive any of the proceeds from the sale of our Common Stock by the Selling Stockholder.

Ascent may sell or otherwise dispose of the Conversion Shares described in this prospectus in a number of different ways and at varying prices. See“Plan of Distribution — Offer and Resale of Common Stock by the Selling Stockholder” for more information about how Ascent may sell or otherwise dispose of the Conversion Shares and the Interest pursuant to this prospectus. Ascent is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended, or the Securities Act.

The Selling Stockholder may sell the shares of our common stock offered by this prospectus from time to time on terms to be determined at the time of sale through ordinary brokerage transactions or through any other means described in this prospectus under the caption“Plan of Distribution.” The shares of common stock may be sold at fixed prices, at market prices prevailing at the time of sale, at prices related to prevailing market price or at negotiated prices.

We will pay the expenses incurred in registering under the Securities Act the offer and sale of the shares of Common Stock to which this prospectus relates by the Selling Stockholder, including legal and accounting fees. See“Plan of Distribution — Offer and Resale of Common Stock by the Selling Stockholder” beginning on page 142.

Our common stock is listed on the Nasdaq Global Market under the symbol “PFSA.” On August 28, 2025, the last sale price for our common stock as reported on the Nasdaq Global Market was $0.41 per share.

We are a “smaller reporting company” as defined under the federal securities laws and, as such, have elected to comply with certain reduced public company reporting requirements for this prospectus and may elect to do so in future filings.

Investing in our securities involves a high degree of risk. See the section entitled“Risk Factors” appearing on page 5 of this prospectus for a discussion of information that should be considered in connection with an investment in our securities.

Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is__________, 2025