SeaStar Medical Holding Corp

As filed with the Securities and Exchange Commission on June 16, 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)

3513 Brighton Blvd, Suite 410

Denver, CO 80216

(844) 427-8100

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Eric Schlorff

Chief Executive Officer

3513 Brighton Blvd, Suite 410

Denver, CO 80216

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copies to:

Joshua Erekson

Daniel Lyman

Dorsey & Whitney LLP

111 South Main Street, Suite 2100

Salt Lake City, UT 84111

(801) 933-7360

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

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, 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.☐

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 this Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold 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.

Up to 4,237,288 Shares of Common Stock and accompanying Warrants to Purchase Up to 4,237,288 Shares of Common Stock

or

Up to 4,237,288 Pre-Funded Warrants to Purchase Up to 4,237,288 Shares of Common Stock and accompanying Warrants to Purchase Up to 4,237,288 Shares of Common Stock

Up to 296,610 Placement Agent Warrants to Purchase Up to 296,610 Shares of Common Stock

Up to 4,533,898 Shares of Common Stock Issuable Upon Exercise of the Warrants, Pre-Funded Warrants and Placement Agent Warrants

We are offering up to 4,237,288 shares of common stock, par value $0.0001 per share (the “Common Stock”), together with warrants to purchase up to shares of common stock (the “Warrants”), pursuant to this prospectus. The assumed combined public offering price for each share of Common Stock, together with an accompanying Warrant to purchase one share of Common Stock, is $1.18, which is equal to the last reported sale price of our Common Stock on The Nasdaq Capital Market on June 13, 2025. The shares of Common Stock and Warrants will be separately issued, but the shares of Common Stock and Warrants will be issued to purchasers in the ratio of one to one. Each Warrant will have an exercise price of $1.18 per share, will be exercisable beginning on the effective date of stockholder approval of the issuance of the shares upon exercise of the Warrants (the “Warrant Stockholder Approval”), provided however, if the Pricing Conditions (as defined below) are met, the Warrant Stockholder Approval will not be required and the Warrants will be exercisable upon issuance (the “Initial Exercise Date”). The Warrants will expire on the anniversary of the Initial Exercise Date. As used herein “Pricing Conditions” means that the combined public offering price per share and accompanying Warrant is such that the Warrant Stockholder Approval is not required under the rules of The Nasdaq Stock Market LLC (“Nasdaq”) because either (i) the offering is an at-the-market offering under Nasdaq rules and such price equals or exceeds the sum of (a) the applicable “Minimum Price” per share under Nasdaq Rule 5635(d) plus (b) $0.125 per whole share of Common Stock underlying the Warrants or (ii) the offering is a discounted public offering where the pricing and discount (including attributing a value of $0.125 per whole share of Common Stock underlying the Warrants) meet the pricing requirements under Nasdaq’s rules.

We are also offering up to 4,237,288 pre-funded warrants (the “Pre-Funded Warrants”) to those purchasers whose purchase of shares of Common Stock in this offering would result in the purchaser, together with its affiliates and certain related parties, beneficially owning more than 4.99% (or, at the election of the purchaser, 9.99%) of our outstanding Common Stock following the consummation of this offering in lieu of the shares of our Common Stock that would result in ownership in excess of 4.99% (or, at the election of the purchaser, 9.99%). Each Pre-Funded Warrant will be exercisable for one share of Common Stock at an exercise price of $0.001 per share. Each Pre-Funded Warrant is being issued together with the same Warrants described above being issued with each share of Common Stock. The assumed combined public offering price for each such Pre-Funded Warrant, together with an accompanying Warrant to purchase one share of Common Stock, is $1.1799, which is equal to the last reported sale price of our Common Stock on The Nasdaq Capital Market on June 13, 2025, minus $0.0001, the exercise price of the Pre-Funded Warrants. Each Pre-Funded Warrant will be exercisable upon issuance and may be exercised at any time until all of the Pre-Funded Warrants are exercised in full. The Pre-Funded Warrants and accompanying Warrants are immediately separable and will be issued separately in this offering, but the Pre-Funded Warrants and Warrants will be issued to purchasers in the ratio of one to one. This prospectus also relates to the offering of the shares of Common Stock issuable upon exercise of the Warrants, Pre-Funded Warrants and Placement Agent Warrants (as defined herein). For each Pre-Funded Warrant sold, the number of shares of Common Stock sold will be reduced on a one-for-one basis.

There is no established public trading market for the Warrants or the Pre-Funded Warrants, and we do not expect a market to develop. We do not intend to apply for listing of the Warrants or the Pre-Funded Warrants on any securities exchange or other nationally recognized trading system. Without an active trading market, the liquidity of the Warrants and the Pre-Funded Warrants will be limited.

This offering will terminate on , 2025, unless we decide to terminate the offering (which we may do at any time in our discretion) prior to that date. We will have one closing for all the securities purchased in this offering. The combined public offering price per share of Common Stock (or Pre-Funded Warrant in lieu thereof) and accompanying Warrants will be fixed for the duration of this offering.

We have engaged (the “Placement Agent”), to act as our exclusive placement agent in connection with this offering. The Placement Agent has agreed to use its reasonable best efforts to arrange for the sale of the securities offered by this prospectus. The Placement Agent is not purchasing or selling any of the securities we are offering and the Placement Agent is not required to arrange the purchase or sale of any specific number of securities or dollar amount. We have agreed to pay to the Placement Agent the Placement Agent fees set forth in the table below, which assumes that we sell all of the securities offered by this prospectus. There is no minimum number of securities or amount of proceeds required as a condition to closing in this offering. In addition, because there is no escrow trust or similar arrangement and no minimum offering amount, investors could be in a position where they have invested in our company, but we are unable to fulfill all of our contemplated objectives due to a lack of interest in this offering. Investors in this offering will not receive a refund in the event that we do not sell an amount of securities sufficient to pursue our business goals described in this prospectus. Further, any proceeds from the sale of securities offered by us will be available for our immediate use, despite uncertainty about whether we would be able to use such funds to effectively implement our business plan. We will bear all costs associated with the offering. See “Plan of Distribution” on page 42 of this prospectus for more information regarding these arrangements.

The assumed combined offering price used throughout this prospectus has been included for illustration purposes only, and may not be indicative of the final offering price. The actual combined public offering price per share of Common Stock and accompanying Warrant and the combined public offering price per Pre-Funded Warrant and accompanying Warrant we are offering and the exercise price and other terms of the Warrants will be negotiated between us and the purchasers, in consultation with the Placement Agent based on the trading of our Common Stock prior to this offering, among other factors. Other factors considered in determining the offering price of the securities we are offering and the exercise price and other terms of the Warrants include the history and prospects of our company, the stage of development of our business, our business plans for the future and the extent to which they have been implemented, an assessment of our management, general conditions of the securities markets at the time of the offering and such other factors as were deemed relevant. The combined public offering price per share of Common Stock and accompanying Warrant and the combined public offering price per Pre-Funded Warrant and accompanying Warrant may be at a discount to the current market price of our Common Stock. Therefore, the recent market price used throughout this prospectus may differ substantially from the combined public offering price.

You should read this prospectus, together with additional information described under the heading “Where You Can Find More Information” carefully before you invest in any of our securities.

We are a “smaller reporting company” under the federal securities laws and, as such, are subject to reduced public company reporting requirements. See “Implications of Being a Smaller Reporting Company.”

We are an “emerging growth company” under the federal securities laws and, as such, are subject to reduced public company reporting requirements. See “Implications of Being an Emerging Growth Company.”

Our Common Stock and warrants exercisable for one share of Common Stock for $11.50 per share (the “Listed Warrants”) are traded on the Nasdaq Stock Market under the symbols “ICU” and “ICUCW,” respectively. On May 20, 2025, the closing price of our Common Stock was $1.285 per share, and the closing price of our Listed Warrants, was $0.0329 per warrant.

On June 7, 2024, we effected a 1-for-25 reverse stock split of the Common Stock (the “Reverse Split”) of our issued and outstanding shares of Common Stock, and our shares of Common Stock began trading on a split-adjusted basis on the Nasdaq Capital Market on June 10, 2024 under the same symbol “ICU”. All of our stock options and warrants outstanding immediately prior to the Reverse Split were proportionally adjusted except for the Listed Warrants and the private placement warrants that were issued as part of the SPAC transaction, which total 16,788,000 outstanding warrants in the aggregate (the “Unadjusted Warrants”). The Unadjusted Warrants retain an $11.50 exercise price each and require the exercise of 25 warrants to purchase one share of Common Stock. Unless otherwise indicated, all other share and per share prices in this prospectus have been adjusted to reflect the Reverse Split.

On June 24, 2024, we received a written notification from the Listing Qualifications staff of Nasdaq that we were not in compliance with the requirement to maintain a minimum market value of listed securities of $35 million (the “MVLS Requirement”), as set forth in Nasdaq Listing Rule 5550(b)(2) (the “MVLS Rule”), because the market value of our listed securities (the “Securities”) had been below $35 million for 30 consecutive business days. We had an initial 180 days, or until December 23, 2024, to regain compliance with the MVLS Requirement.

On December 24, 2024, we received written notification (the “Notification”) from Nasdaq stating that we had not regained compliance with the MVLS Requirement. Pursuant to the Notification, the Securities were subject to delisting from Nasdaq on January 3, 2025, unless we requested a hearing before the Nasdaq Hearings Panel (the “Panel”) by December 31, 2024.

On March 11, 2025, we received a decision letter (the “Letter”) from the Panel, granting our request to continue its listing on Nasdaq, subject to certain conditions. The Panel’s decision provides us with an exception until June 22, 2025, to demonstrate compliance with the MVLS Requirement.

Investing in our securities involves a high degree of risk. You should read “Risk Factors” beginning on page 6 of this prospectus, and under similar headings in the documents incorporated by reference in this prospectus, as well as in any amendments or supplements to this prospectus, to read about factors to consider before purchasing our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Delivery of the securities to the purchasers is expected to be made on or about , 2025, subject to the satisfaction of customary closing conditions.

The date of this prospectus is , 2025.

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