SEC Form S-8 filed by SeaStar Medical Holding Corporation

As filed with the Securities and Exchange Commission on July 21, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

SeaStar Medical Holding Corporation

(Exact name of registrant as specified in its charter)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a 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. ☐

EXPLANATORY NOTE

This Registration Statement on Form S-8 (the “Registration Statement”), relating to the Amended and Restated SeaStar Medical Holding Corporation 2022 Omnibus Incentive Plan (as amended, the “Incentive Plan”), is being filed for the purpose of registering: (i) 689,500 shares (the “Shares”) of common stock, par value $0.0001 per share (the “Common Stock”), of SeaStar Medical Holding Corporation (the “Registrant”), reserved for issuance pursuant to an amendment to the Incentive Plan, which was approved by shareholders on June 17, 2026, and (ii) pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the “Securities Act”), any additional shares of Common Stock that become issuable under the Incentive Plan by reason of any stock dividend, stock split, or other similar transaction.

The Shares are securities of the same class and relate to the same employee benefit plan as (i) the 5,080 shares of Common Stock (after giving effect to both of the reverse stock splits referenced below) registered for issuance pursuant to the Registration Statement on Form S-8, File No. 333-270070, filed by the Registrant with the Securities and Exchange Commission (the “SEC”) on February 27, 2023, (ii) the 4,720 shares of Common Stock (after giving effect to both of the reverse splits referenced below) registered for issuance pursuant to the Registration Statement on Form S-8, File No. 333-276978, filed by the Registrant with the SEC on February 9, 2024, (iii) the 47,246 shares of Common Stock (after giving effect to the January 5, 2026 reverse split referenced below) registered for issuance pursuant to the Registration Statement on Form S-8, File No. 333-286671, filed by the Registrant with the SEC on April 22, 2025, and (iv) the 150,000 shares of Common Stock (after giving effect to the January 5, 2026 reverse split referenced below) registered for issuance pursuant to the Registration Statement on Form S-8, File No. 333-289421, filed by the Registrant with the SEC on August 8, 2025 (collectively, the “Prior Registration Statements”). This Registration Statement is filed in accordance with General Instruction E to Form S-8. Accordingly, pursuant to General Instruction E, the Registrant hereby incorporates by reference herein the contents of the Prior Registration Statements and hereby deems such contents to be a part hereof, except as otherwise updated or modified by this Registration Statement.

The Reverse Stock Splits

On June 7, 2024, the Company effected a 1-for-25 reverse-stock split (the “2024 Reverse Stock Split”) of its issued and outstanding shares of Common Stock. Following the effect of the 2024 Reverse Stock Split, each 25 shares of the Company’s common stock that were issued and outstanding automatically converted into one outstanding share of common stock.

On January 5, 2026, the Company effected a 1-for-10 reverse-stock split (the “2026 Reverse Stock Split,” together with the 2024 Reverse Stock Split, the “Reverse Stock Splits”) of its issued and outstanding shares of common stock, par value $0.0001. Following the effect of the 2026 Reverse Stock Split, each 10 shares of Common Stock that were issued and outstanding automatically converted into one outstanding share of common stock.

Combined, this had the effect of a 1-for-250 reverse stock split. All share amounts referenced above and otherwise in this Registration Statement, depending on the date of the prior registration statements, give effect to the Reverse Stock Splits.

PART II.

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.         Incorporation of Documents by Reference.

The following documents filed by the Registrant with the SEC pursuant to the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”), are hereby incorporated by reference into this Registration Statement:

All other reports and other documents subsequently filed with the SEC by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of Exchange Act prior to the filing of a post-effective amendment to this registration statement which indicates that all securities offered have been sold or which deregisters all securities then remaining unsold (other than those furnished pursuant to Item 2.02 or Item 7.01 of Form 8-K or other information deemed to have been “furnished” rather than “filed” in accordance with the SEC’s rules), shall be deemed to be incorporated by reference in this Registration Statement and to be part hereof from the date of filing of such reports and documents.

Any statement contained in a document incorporated or deemed to be incorporated by reference in this Registration Statement shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained in this Registration Statement, or in any other subsequently filed document that also is or is deemed to be incorporated by reference in this Registration Statement, modifies or supersedes such prior statement. Any statement contained in this Registration Statement shall be deemed to be modified or superseded to the extent that a statement contained in a subsequently filed document that is or is deemed to be incorporated by reference in this Registration Statement modifies or supersedes such prior statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Item 8.         Exhibits.

A list of exhibits filed herewith is contained in the Exhibit Index that immediately precedes such exhibits and is incorporated herein by reference.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Denver, State of Colorado on this 21st day of July, 2026.

SeaStar Medical Holding Corporation

POWER OF ATTORNEY

Each of the undersigned, whose signature appears below, hereby constitutes and appoints Eric Schlorff as his or her true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any or all amendments to this registration statement and to file the same with all exhibits thereto and other documents in connection therewith, with the SEC, granting unto said attorneys-in-fact and agents full power and authority to do and perform each and every act and thing necessary or appropriate to be done with respect to this registration statement or any amendments hereto in the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or his or their substitute or substitutes, may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement on Form S-8 has been signed by the following persons in the capacities indicated below on July 21, 2026.