SeaStar Medical Holding Corp

Note1. Description of Business

Organization and Description of Business

SeaStar Medical Holding Corporation, a Delaware corporation (“SeaStar”) and its wholly owned subsidiary, SeaStar Medical, Inc., are collectively referred to as the “Company”. SeaStar Medical, Inc. was incorporated as a Delaware corporation in* June 2007,*and it is headquartered in Denver, Colorado. The Company is principally engaged in the research, development, and commercialization of a platform medical device technology designed to modulate inflammation in various patient populations. The initial target of this technology is for the treatment of patients with acute kidney injuries ("AKI"), but through additional Breakthrough Device Designation (“BDD”) from the Food and Drug Administration (“FDA”), has expanded into treatments of patients with cardiorenal syndrome awaiting left ventricular assist device implantation, patients with hepatorenal syndrome, patients with end stage renal disease and adult and pediatric patients undergoing cardiac surgery. The BDD enables the potential for a speedier pathway to approval and the ability to have more frequent and flexible meetings with the FDA.

The Company received FDA approval on* February 21, 2024,under a Humanitarian Device Exemption (“HDE”) for the Company’s pediatric version of its Selective Cytopheretic Device ("SCD") therapy. It is the only FDA approved product for use in pediatric patients with AKI due to sepsis or a septic condition requiring kidney replacement therapy. The Company shipped itsfirst* commercial pediatric SCD (“QUELIMMUNE”) in* July 2024.*In addition, the Company is currently conducting a pivotal clinical trial to assess the safety and efficacy of the SCD therapy in critically ill adult patients with AKI requiring continuous renal replacement therapy (“CRRT”).

On* October 28, 2022,*LMF Merger Sub, Inc., a wholly owned subsidiary of LMF Acquisition Opportunities, Inc. (“LMAO”) merged with and into SeaStar Medical, Inc. (the “Business Combination”), with SeaStar Medical, Inc. surviving the Business Combination as a wholly owned subsidiary of LMAO. Following the consummation of the Business Combination, LMAO was renamed “SeaStar Medical Holding Corporation.”

Basis of Presentation and Consolidation

The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules and regulations, certain notes or other financial information normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The interim unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal, recurring adjustments that are necessary to present fairly the Company’s results for the interim periods presented. The results from operations for thenine months ended* September 30, 2025*, arenot necessarily indicative of the results to be expected for the year ending* December 31, 2025*, or for any future annual or interim period.

The accompanying interim unaudited condensed consolidated financial statements should be read in conjunction with the annual consolidated financial statements and the related notes for the year ended* December 31, 2024*. There have beenno material changes in our significant accounting policies as described in our Annual Report on Form10-K for the year ended* December 31, 2024*.

The interim unaudited condensed consolidated financial statements include the consolidated accounts of the Company’s wholly owned subsidiary, SeaStar Medical, Inc. All significant intercompany transactions have been eliminated in consolidation.

On* June 7, 2024,the Company effected a1*-for-25 reverse stock split (the “Reverse Stock Split”) of its issued and outstanding shares of common stock, par value $0.0001 (the “common stock”). Following the effect of the Reverse Stock Split, each 25 shares of the Company’s common stock that were issued and outstanding automatically converted intoone outstanding share of common stock. All stock options and warrants of the Company outstanding immediately prior to the Reverse Stock Split were proportionally adjusted except for the Listed Warrants and the private placement warrants that were issued as part of the SPAC transaction that closed on* October 28, 2022,which total 16,788,000 outstanding warrants in the aggregate (the “Unadjusted Warrants”). The Unadjusted Warrants retained an $11.50 exercise price each and require the exercise of 25 warrants to purchaseone* share of common stock. Unless otherwise indicated, all other share and per share amounts in this quarterly report reflect the effect of the Reverse Stock Split. The par value of the Company’s common stock remained unchanged at $0.0001 per share and the number of authorized shares of common stock remained the same after the Reverse Stock Split.

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Segment Information

The Company is comprised of asingle reportable segment, its Device Segment. This organizational structure aligns with how our Chief Operating Decision Maker (“CODM”), the Chief Executive Officer, manages the Company’s business, including resource allocation and performance assessment. The Company is focused entirely on the development, regulatory approval and commercialization of the Company’s adult and pediatric Selective Cytopheretic Devices (SCDs). The Company had a total of 17 employees at* September 30, 2025*, and total assets of $15.5 million and $4.7 million, as of* September 30, 2025*, and* December 31, 2024*, respectively.

For segment reporting purposes, the CODM uses operating profit/(loss) to evaluate segment performance and allocate resources. As a Company that only recently began limited commercial sales of QUELIMMUNE, the CODM is primarily focused on evaluating the overall spending for research and development activities needed to fund further development of the SCDs, and general and administrative activities incurred to support the research and development activities of the Company. Accounting policies associated with the Company’s sole segment are the same as those described in Note2. See Note14 for Segment Reporting information.

All of the Company’s sales are located within the United States. As of the date of this report, the Company has obtained regulatory approval for commercial sales in the U.S. of QUELIMMUNE from the FDA. The Company doesnot have any inter-entity sales or transfers.

Liquidity and Going Concern

The Company incurred losses of $9.2 million for thenine months ended* September 30, 2025*. As of* September 30, 2025*, the Company has an accumulated deficit of $148.8 million and cash of $13.8 million. The Company doesnot believe that its cash on hand will be sufficient to enable it to fund its operations, including clinical trial expenses and capital expenditure requirements for at least12 months from the issuance of these unaudited condensed consolidated financial statements. The Company believes that these conditions raise substantial doubt about its ability to continue as a going concern.

The Company’s need for additional capital will depend in part on the scope and costs of its development activities. To date, the Company has generated insufficient revenue from the sales of its commercialized product, QUELIMMUNE to fund its operations. Its ability to generate meaningful product revenue will depend on the progress of the commercial launch of QUELIMMUNE and successful development and eventual commercialization of the adult SCD. Until such time, if ever, the Company expects to finance its operations through the sale of equity or debt securities, borrowing under credit facilities, or through potential collaborations, other strategic transactions or government and other grants. Adequate capital* may**not* be available to the Company when needed or on acceptable terms.

If the Company is unable to raise capital, it could be forced to delay, reduce, suspend, or cease its research and development programs or any future commercialization efforts, which would have a negative impact on its business, prospects, operating results and financial condition. The accompanying unaudited condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern and donot include adjustments that might result from the outcome of this uncertainty. This basis of accounting contemplates the recovery of the Company’s assets and the satisfaction of liabilities in the normal course of business.

Risks and Uncertainties

The Company is subject to risks common to early-stage companies in the medical technology industry including, butnot limited to, new medical and technological innovations, dependence on key personnel, protection of proprietary technology, and product liability. There can beno assurance that the Company’s products or services will be accepted in the marketplace, nor can there be any assurance that any future products or services can be developed or deployed at an acceptable cost and with appropriate performance characteristics, or that such products or services will be successfully marketed, if at all. These factors could have a materially adverse effect on the Company’s future financial results, financial position and cash flows.

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Note2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements and reported amounts of revenues and expenses during thethree andnine months ended* September 30, 2025*. Significant estimates include the (i) unbilled clinical trial costs, and (ii) stock-based compensation expense. Although actual results could differ from those estimates, such estimates are developed based on the best information available to management and management’s best judgments at the time.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to a significant concentration of credit risk consist primarily of cash. Periodically, the Company* may*maintain deposits in financial institutions in excess of government insured limits. Any loss incurred or a lack of access to such funds could have a significant adverse impact on the Company’s financial condition, results of operations, and cash flows.

Accounts Receivable, net

The need for a credit loss allowance is evaluated each reporting period based on the Company’s assessment of the creditworthiness of its customers or any other potential circumstances that could result in a credit loss. The Company uses an aging schedule method for estimating expected credit losses. As the Company only commenced commercial operations on* July 1, 2024,with a limited customer base, the Company’s estimates are based on customer specific facts, until such time that the Company has developed sufficient collection history data in which to apply a portfolio-wide expected credit loss estimate based on an aging schedule (see Note4*).

Fair Value of Financial Instruments

The following provides a summary of those assets or liabilities for which the Company is required to measure at fair value either on a recurring basis, the valuation techniques and summary of inputs used to arrive at the measure of fair value. Changes in fair value of these assets or liabilities are recognized as a component of net loss in the consolidated statements of operations. Changes in fair value of these assets or liabilities are considered unrealized gains or losses and therefore are classified as non-cash adjustments to reconcile net income to operating cash flows. Significant increases (decreases) in unobservable inputs used in fair value measurements could, in isolation, potentially result in a significantly lower or higher valuation for those assets or liabilities requiring recurring fair value measurements at each reporting date.

The Company uses a Black-Scholes option pricing model to estimate the fair value of liability classified warrants, using standard option pricing inputs such as the strike price of each warrant tranche, estimated volatility, time to maturity, and the risk-free interest rate. The risk-free interest rate is the U.S. Treasury rate at the date of issuance, and the time to maturity is based on the contractual life at the date of issuance, which is an interpolated value based on the remaining term of each individual instrument. The change in fair value of the liability classified warrants in each reporting period is recorded to the change in fair value of liability classified warrants in the consolidated statements of operations.

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Revenue Recognition

Overall

Under ASC606, Revenues from Contracts with Customers("Topic606") the Company recognizes revenue when a customer obtains control of promised goods or services, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of Topic606, the Company evaluates the following criteria: (i) identify the contract with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) performance obligations are satisfied.

At contract inception, once the contract is determined to be within the scope of Topic606, the Company assesses whether the goods or services promised within each contract are distinct and, therefore, represent a separate performance obligation. Goods and services that are determinednot to be distinct are combined with other promised goods and services until a distinct combined performance obligation is identified. The Company then allocates the transaction price to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled, subject to the constraint on variable consideration. The Company constrains revenue by giving consideration to factors that could otherwise lead to a probable reversal of revenue. Variable consideration isnot constrained if the potential reversal of cumulative revenue recognized at the contract level isnot significant.

The Company records any payments received from customers prior to the Company fulfilling its performance obligation(s) as contract obligations. Amounts expected to be recognized as revenue within theone year following the balance sheet date are classified as current contract obligations. Amountsnot expected to be recognized as revenue within theone year following the balance sheet date are classified as contract obligations, net of current portion. See Note3 – Revenue and Contract Obligations for further details.

Product Sales Revenue

The Company sells its products directly to end-user qualified customers using the Company’s own internal commercial/sales resources.

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The Company will continue to monitor all of the above as the Company continues to commercialize and increase its customer base, which could result in each distributor or end-user customer agreement having its own unique terms and conditions, that will potentially impact the timing and amount of revenue recognition pursuant to U.S. GAAP.

Cost of Goods Sold

Prior to* July 2024,the Company manufactured/assembled QUELIMMUNE and adult SCDs only for research oriented and/or clinical trial related activities. Inventory purchased prior to July 2024was expensed as a period expense at the time of purchase as a research and development expense. Accordingly, all QUELIMMUNE units sold prior to thethree* months ended* June 30, 2025,hadno* recognized inventory value. During thethree andnine months ended* September 30, 2025*, the Company recognized approximately $14 thousand and $41 thousand for cost of goods sold, respectively.

As the Company continues to procure inventory, the Company will recognize the cost of materials to inventory. Use of inventory for QUELIMMUNE will be charged to cost of goods sold while inventory used for adult SCDs will be charged to research and development upon shipment.

Funded Research & Development Expense

During thethree months ended* September 30, 2025*, the Company entered into an agreement to provide contract research services to an outside party, which involves a study of the Company's selective cytopheretic device relating to patients with severe, chronic heart failure. The Company is able to bill the outside party for a certain portion of the costs incurred to provide these services. The Company will own and is able to benefit from the knowledge gained from the results of this study. Accordingly, the Company will account for any funds paid by the outside party to the Company as a reimbursed expense, in accordance with ASC730-20 as a* funded research and development arrangement. Accordingly, any amounts incurred and billed will offset the Company's operating expenses categorized as research and development expense on the Company’s condensed consolidated statement of operations for thethree* andnine months ended* September 30, 2025*. The reimbursed expenses for thethree andnine months ended* September 30, 2025* totaled approximately $0.1 million and $0.3 million, respectively. No funded research and development agreement existed in2024.

Emerging Growth Company Status

The Company is an “emerging growth company”, as defined in the Jumpstart Our Business Startups Act of2012 (“JOBS Act”). Under the JOBS Act, emerging growth companies can take advantage of an extended transition period for complying with new or revised accounting standards, delaying the adoption of these accounting standards until they apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1)no longer an emerging growth company or (2) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act.

Recently issued accounting standards

Accounting Standards Update2024*-03 — In November 2024,the FASB issued ASU2024*-03 -Income Statement - Reporting Comprehensive Income–* Expense Disaggregation (Subtopic220-40): Disaggregation of Income Statement Expenses*. ASU2024-03 requires the disclosure of additional information related to certain costs and expenses, including amounts of inventory purchases, employee compensation, and depreciation and amortization included in each income statement line item. The ASU is effective for annual periods beginning after* December 15, 2026,and interim periods beginning after December 15, 2027,*with early adoption permitted. The Company is currently evaluating the impact of adopting this guidance on its consolidated financial statements and disclosures.

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Accounting Standards Update2023*-09 — In December 2023,the FASB issued ASU2023*-09 Income Taxes (Topic740*) Improvements to Income Tax Disclosures*. ASU2023-09 enhances the transparency and decision usefulness of income tax disclosures. The amendments in this update are effective for public business entities for annual periods beginning after* December 15, 2024.Early adoption is permitted, but the Company didnot* elect to early adopt. The Company is currently assessing the impact of this guidance on its consolidated financial statements and disclosures, however the impact from the adoption of this guidance, if any, will be reflected in the Company's Annual Report to Form10-K for the year ending* December 31, 2025.*

Note3. Revenues and Contract Obligations

There are and wereno contract assets or liabilities as of and at any time during thenine months ended* September 30, 2025.This is because the Company's current contracts with customers donot* contain features, terms or conditions that would give rise to such contract assets or liabilities.

Revenue by Geographic Location

The Company’s sales are entirely in the United States of America, as it doesnot have any regulatory approval to sell elsewhere as of* September 30, 2025*.

Note4. Accounts Receivable, net

The table below presents the opening and closing balances of accounts receivable, on a gross and net basis, with the total change in expected credit losses.

Note5. Accrued Expenses

Accrued expenses consisted of the following amounts as of* September 30, 2025*, and* December 31, 2024*:

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Note6. Notes Payable

Insurance Financing

In* October 2024,the Company entered into a financing arrangement with a lender to finance a portion of the annual premium of an insurance policy in the amount of $0.7 million. As of September 30, 2025*, the Company paid the entire balance andno remaining obligation existed.

Note7. Equity Transactions

**** August 2025Offering**

On* August 1, 2025,the Company closed on a registered direct offering with certain institutional investors (the "August 2025Offering"), pursuant to which the Company sold and issued to the Purchasers, (i)4,960,544 shares of the Company’s common stock par value $0.0001 per share and (ii) in a concurrent private placement, warrants to purchase up to an aggregate of 4,960,544 shares of Common Stock (the “August 2025Common Warrants”) at an exercise price of $0.762 per share. The combined offering price for each share of common stock and accompanying Common Warrant was $0.887. The Common Warrants are exercisable upon issuance and will expire on thefifth* anniversary of the effective date of the registration statement filed by the Company registering the resale of the shares of common stock underlying the Common Warrants.

The Company paid approximately $0.5 million in offering costs comprised of a cash fee of 7.00%, a management fee of 1.00%, legal fees and other fees. Also in connection with the* August 2025Offering, the Company agreed to issue to the Placement Agent or its designees warrants (the “August 2025Placement Agent Warrants”) to purchase up to an aggregate of 347,238 shares of Common Stock (the “Placement Agent Warrant Shares”). The Placement Agent Warrants have an exercise price of $1.1088 per share (which represents 125% of the offering price per Share and accompanying Common Warrant), are exercisable upon issuance and will expire on July 31, 2030*and will be exercisable upon issuance.

The* August 2025Common Warrants and August 2025Placement Agent Warrants collectively herein are referred to as the “August 2025*Warrants”.

In accordance with ASC815-40, Derivatives and Hedging-Contracts in Entity’s own Equity, the Company determined that all of the* August 2025Warrants issued in connection with the August**2025* Offering met the conditions for equity classification and were included as a component of stockholders’ equity (deficit).

**** July 2025Offering**

On* July 11, 2025,the Company closed on a registered direct offering with certain institutional investors (the “July**2025* Offering”), pursuant to which the Company sold and issued to the Purchasers, (i)4,841,232 shares of the Company’s common stock par value $0.0001 per share and pre-funded warrants to purchase up to 401,232 shares of Common Stock (the* “July 2025Pre-Funded Warrants”) at an exercise price of $0.001 per share (fully exercised concurrent with the July 2025Offering), and (ii) in a concurrent private placement, warrants to purchase up to an aggregate of 5,242,464 shares of Common Stock (the “July 2025Common Warrants”) at an exercise price of $0.638 per share. The combined offering price for each share of common stock and accompanying Common Warrant was $0.763. The Common Warrants are exercisable upon issuance and will expire on thefifth* anniversary of the effective date of the registration statement filed by the Company registering the resale of the shares of common stock underlying the Common Warrants.

The Company paid approximately $0.4 million in offering costs comprised of a cash fee of 7.00%, a management fee of 1.00%, legal fees and other fees. Also in connection with the* August 2025Offering, the Company agreed to issue to the Placement Agent or its designees warrants (the “August 2025Placement Agent Warrants”) to purchase up to an aggregate of 347,238 shares of Common Stock (the “Placement Agent Warrant Shares”). The Placement Agent Warrants have an exercise price of $1.1088 per share (which represents 125% of the offering price per Share and accompanying Common Warrant), are exercisable upon issuance and will expire on July 31, 2030*and will be exercisable upon issuance.

The* July 2025Common Warrants, July 2025Pre-Funded Warrants and July 2025Placement Agent Warrants collectively herein are referred to as the “July**2025* Warrants”.

In accordance with ASC815-40, Derivatives and Hedging-Contracts in Entity’s own Equity, the Company determined that all of the* July 2025Warrants issued in connection with the July**2025* Offering met the conditions for equity classification and were included as a component of stockholders’ equity (deficit).

**** June 2025Offering**

In* June 2025,the Company did a best efforts public offering (the “June 2025Offering”) pursuant to which the Company issued aggregate of (i)4,935,385 shares of the Company's common stock, (ii)1,218,462 pre-funded warrants to purchase up to 1,218,462 shares of Common Stock (the “June 2025*Pre-Funded Warrants”) with an exercise price of $0.0001, (iii)6,153,847 Series A warrants to purchase up to 6,153,847 shares of Common Stock with an exercise price of $0.65 (the “Series A Warrants”), and (iv)6,153,847 Series B warrants to purchase up to 6,153,847 shares of Common Stock at an exercise price of $0.65 (the “Series B Warrants”).

The Company received aggregate gross proceeds from the* June 2025Offering of approximately $4.0 million, before deducting fees to H.C. Wainwright & Co. (“Wainwright”) and other estimated offering expenses payable by the Company. The June 2025Pre-Funded Warrants willnot* expire and are exercisable upon issuance and at any time until all of the* June 2025Pre-Funded Warrants are exercised in full. As of September**30,* 2025, a total of 1,218,462 pre-funded warrants were exercised withno * June 2025*Pre-Funded Warrants outstanding.

The Series A Warrants and Series B Warrants were immediately exercisable with the Series A warrants expiring in* June 2030and the Series B Warrants expiring in December 2026.*

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The Company paid approximately $0.4 million in fees to Wainwright and issued 430,769 warrants (the* "June 2025PA Warrants") to purchase shares of the Company's common stock at an exercise price of $0.8125. The2025* PA Warrants were exercisable upon issuance and expire on* June 20, 2030.The June 2025PA Warrants, Series A Warrants and Series B Warrants are herein defined as the "June 2025*Warrants".

In accordance with ASC815-40, Derivatives and Hedging-Contracts in Entity’s own Equity, the Company determined that all the different warrants issued in connection with the* June 2025*Offering met the conditions for equity classification and were included as a component of stockholders’ equity (deficit).

Standby Equity Purchase Agreement

On* April 25,*2025, the Company entered into a standby equity purchase agreement (“Common Stock Purchase Agreement”) and related registration rights agreement (the “Registration Rights Agreement”) with Lincoln Park Capital Fund, LLC (“Lincoln Park”), collectively the “SEPA”. Pursuant to the Common Stock Purchase Agreement, the Company has the right, butnot the obligation, to direct Lincoln Park to purchase up to $15.0 million in aggregate gross purchase price of newly issued shares of Common Stock, subject to certain limitations and conditions as described below (the “SEPA Program”) at a purchase price equal to 97% of the lesser of (i) the lowest sale price of the common stock on the purchase date or (ii) average of thethree lowest closing sale prices of the common stock over the lastten business days prior to the purchase date.

The Company controls the timing and amount of any sales to Lincoln Park, which depend on a variety of factors including, among other things, market conditions, the trading price of the Company’s common stock, and determinations by the Company as to appropriate sources of funding for its business and operations. However, Lincoln Park’s obligation to purchase shares is subject to certain conditions, including the daily trading volume of the Company’s stock. In all instances, the Company* maynot* sell shares of Common Stock under the Purchase Agreement if it would result in Lincoln Park and its affiliate beneficially owning more than 9.99% of outstanding voting power or shares of the Common Stock at anyone point in time. Additionally, the Company* maynot* issue more than 1,981,163 shares of common stock under the Common Stock Purchase Agreement for less than $1.25 unless stockholder approval is obtained.

As part of the SEPA, the Company agreed to pay Lincoln Park 236,406 shares of the Company’s common stock, valued at approximately $0.3 million on the date of issuance,* April 25, 2025 (*the “Commitment Fee”).

The Company evaluated the contract that includes the right to require Lincoln Park to purchase shares of common stock in the future (“put right”) considering the guidance in ASC815-40,* Derivatives and Hedging*—* Contracts on an Entity*’s Own Equity and concluded that it is an equity-linked contract that doesnot qualify for equity classification, and therefore requires fair value accounting. The Company analyzed the terms of the freestanding put right and concluded that it has an immaterial value as of* September 30, 2025*.

The Company hasnot yet raised any capital nor issued any shares from the use of the SEPA.

**** February 2025Offering**

In* January 2025,the Company entered into a Securities Purchase Agreement with an institutional investor (the"Q1* 2025 SPA"), pursuant to which the Company issued on* February 3, 2025,to the investor, (i) in a registered direct offering,713,000 shares of the Company’s common stock, and pre-funded warrants to purchase 2,816,412 shares of Common Stock (the “February 2025Pre-Funded Warrants”) with an exercise price of $0.0001 per share, and (ii) in a concurrent private placement, warrants to purchase 3,529,412 shares of common stock with an exercise price of $1.70 ( “February 2025Common Warrants”). Such registered direct offering and concurrent private placement are referred to herein as the “February 2025Offering". Collectively, the warrants are referred herein as “the February 2025*Warrants”.

The Company received aggregate gross proceeds from the* February 2025Offering of approximately $6.0 million, before deducting fees to H.C. Wainwright & Co. (“Wainwright”) and other estimated offering expenses payable by the Company. The February 2025Pre-Funded Warrants didnot* have a set expiration and were exercisable upon issuance and at any time until all of the* February 2025Pre-Funded Warrants were exercised in full. As of September 30, 2025*, a total of 2,816,412 pre-funded warrants were exercised, leavingno remaining* February 2025*Pre-Funded Warrants outstanding.

The* February 2025Common Warrants became exercisable on March 28, 2025,the effective date of stockholder approval for the issuance of the shares of common stock issuable upon exercise of the warrants and expire on March 28, 2030.*

Prior to their exercise, the* February 2025*Pre-Funded Warrants had dividend participation rights, and any unexercised pre-funded warrants are included in the Company's weighted-average shares outstanding for calculation the Company's net loss per share.

In connection with the* January 2025Offering, the Company amended the exercise price of the Series A and Series B common warrants (collectively “January 2024Warrants”), issued in a financing transaction with the institutional investor in January 2024,to $1.70 from the original exercise price of $20.76. Furthermore, the expiration date of 216,816 of the January 2024Warrants was extended to January 30, 2029,upon stockholder approval on March 28, 2025.With the amendment to the expiration date, all of the January 2024Warrants now expire in2029.*

The Company paid approximately $0.4 million in fees to Wainwright and issued 247,059 warrants (the* "February 2025PA Warrants") to purchase shares of the Company's common stock at an exercise price of $2.13. The2025* PA Warrants were exercisable upon issuance and expire on* January 30, 2029.The2025* PA Warrants and* February 2025Common Warrants are herein defined as the "February 2025*Warrants".

In accordance with ASC815-40, Derivatives and Hedging-Contracts in Entity’s own Equity, the Company determined that all the different warrants issued or amended in connection with the* February 2025*Offering met the conditions for equity classification and were included as a component of stockholders’ equity/(deficit).

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At-The-Market Offering

On* August 20, 2024,the Company entered into an At-The-Market Offering Agreement (the “ATM Agreement”) with Wainwright as sales agent, to sell shares of its common stock, from time to time, through an “at the market offering” program under which Wainwright will act as sales agent. The sales, if any, of the Company’s Common Stock made under the ATM Agreement will be made by any method permitted by law deemed to be an “at the market offering” as defined in Rule415* promulgated under the Securities Act of1933, as amended (the “Securities Act”), including sales made directly on or through the Nasdaq Capital Market or on any other existing trading market for the Company’s common stock (the “ATM”).

Through* September 30, 2025*, the Company has raised approximately $8.6 million, net of offering costs utilizing the ATM since inception in* August 2024,issuing 6.9 million shares of the Company’s Common Stock. During thenine* months ended* September 30, 2025*, the Company raised approximately $4.2 million, net of offering costs, issuing approximately 5.1 million shares of the Company's common stock.

Note8. Warrants

The Company issued warrants in connection with various financing transactions. The Company had the following warrants outstanding at* September 30, 2025*, and* December 31, 2024*:

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The following tables provide the weighted-average strike price and time to maturity for each warrant share equivalent outstanding for each warrant tranche as of* September 30, 2025* and* December 31, 2024*(*):

() The above warrant tranches can include classes of warrants with original or amended terms ranging fromeighteen* months tofive years.

Below is the warrant activity for thenine months ended* September 30, 2025*, for those warrants with activity during thenine months ended* September 30, 2025*:

During thethree andnine months ended* September 30, 2025*, the Company incurred a gain of approximately $16 thousand and $32 thousand from the mark-to-market adjustment for all remaining liability classified warrants, respectively.

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Note9. Stock-Based Compensation Awards

The following table sets forth the total stock-based compensation cost included in the Company’s unaudited condensed consolidated statements of operations for the periods indicated:

Equity Incentive Plan - Summary

2022 Omnibus Incentive Plan

The Company’s Board of Directors adopted, and the stockholders approved the2022 Omnibus Incentive Plan to provide long-term incentive for its employees and non-employee service providers. The vesting of stock options is stated in each individual grant agreement, which is generallyone tofour years. Options granted expire 10 years after the date of grant.

2019 Stock Incentive Plan

The Company’s Board of Directors adopted the2019 Stock Incentive Plan on* February 25, 2019,to provide long-term incentive for its employees and non-employee service providers. The Stock Incentive Plan was terminated on October 28, 2022,andno* further awards were granted under such plan.

Stock Options

Option activity for thenine months ended* September 30, 2025*, is as follows:

2022 Omnibus Incentive Plan - Stock Options

2019 Omnibus Incentive Plan - Options

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Restricted Stock Units

A summary of the Company’s restricted stock unit (“RSU”) activity is as follows:

2022 Omnibus Incentive Plan - RSUs

2019 Stock Incentive Plan - RSUs

Note10. Commitments and Contingencies

Lease Agreements

The Company is part of a membership agreement for shared office space and can cancel at any time. Rent expense was approximately $23 thousand and $60 thousand for thethree andnine months ended* September 30, 2025* respectively, and approximately $8 and $24 thousand for thethree andnine months ended* September 30, 2024*, respectively.

Litigation

Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. From time to time, the Company* may*become involved in legal proceedings arising in the ordinary course of business.

2024 Securities Class Action Lawsuit

On* July 5, 2024,Forrest A K Wells (the “Plaintiff”), a purported stockholder of the Company, filed a putative class action complaint in the United States District Court for the State of Colorado, captioned Wells v. SeaStar Medical Holding Corporation et al, CaseNo.* 1:24-cv-0187 (D. Colorado) (the “Class Action”). The Class Action alleges that the Company, its Chief Executive Officer and former Chief Financial Officer made or caused to be made material misstatements or omissions regarding the Company’s business and operations, allegedly culminating in the Company’s restatement of its consolidated financial statements, disclosed in a Form8-K and filed on* March 27, 2024.The Class Action asserts claims pursuant to the Securities Exchange Act of1934,* including Section10(b), Rule10b-5 promulgated thereunder and Section20(a). The Class Action seeks to recover, among other remedies, compensatory damages. The Company intends to vigorously defend the action.

The Company hasnot recognized a contingent liability for this Class Action event as it doesnot qualify for the recognition criteria under ASC450, Contingencies.

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Note11. Fair Value Measurements

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Inputs used to measure fair value are classified into the following hierarchy:

Level1 – quoted prices in active markets for identical assets and liabilities.

Level2 – other significant observable inputs (including quoted prices for similar assets and liabilities, interest rate, credit risk, etc.).

Level3 – significant unobservable inputs (including the Company’s own assumptions in determining the fair value of assets and liabilities).

The fair value of the warrants liability is classified as Level3 in the fair value hierarchy.

Fair Value Measurement Hierarchy

The following tables presents the Company’s financial assets and/or liabilities that were accounted for at fair value on a recurring basis as of* September 30, 2025* and* December 31, 2024*, by level within the fair value hierarchy. There wereno non-recurring fair value measurements, as the Company doesnot have any long-lived assets, including fixed assets, intangible assets, or goodwill which can require non-recurring measurements for impairment.

Summary of Level3 Input Changes**

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The following table presents the changes in the forward option-prepaid forward contracts, convertible notes measured at fair value, warrants liability, and the notes derivative liability for thenine months ended* September 30, 2025* (in thousands):

Level3* Inputs*

For assets or liabilities for which the Company is required to remeasure the fair value on a recurring basis at each reporting date, generally the Company is required to disclose certain quantitative data related to the inputs used at the most recent reporting period date. However, for those assets or liabilities for which the Company has elected to take the fair value option in accordance with ASC825, Financial Instruments, then such quantitative disclosures arenot required.

Liability Classified Warrants

The liability classified warrants as of* September 30, 2025* and* December 31, 2024*, includethree classes of warrants, and therefore, the range of assumptions used has been provided. Significant assumptions used in valuing warrants which require liability classification were as follows as of* September 30, 2025* and* December 31, 2024*.

Note12. Income Taxes

In accordance with U.S. GAAP, a valuation allowance should be provided if it is more likely thannot that some or all of the Company’s deferred tax assets willnot be realized. The Company’s ability to realize the benefit of its deferred tax assets will depend on the generation of future taxable income. Except as noted below, due to the uncertainty of future profitable operations and taxable income, the Company has recorded a full valuation allowance against its net deferred tax assets. The Company has recognized an insignificant provision for certain minimum state taxes of approximately $3 thousand as of* September 30, 2025*.

The Company believes its tax filing position and deductions related to tax periods subject to examination will be sustained under audit and, therefore, hasno reserve for uncertain tax positions.

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Note13. Net Loss Per Share

The following table presents the calculation of basic and diluted net loss per share (in thousands except share and per share information):

The following weighted-average outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive:

Note14. Segment Reporting

The Company is comprised of asingle reportable segment, its Device Segment. This organizational structure aligns with how our Chief Operating Decision Maker (“CODM”), the Chief Executive Officer, manages the Company’s business, including resource allocation and performance assessment. The Company is focused entirely on the development, regulatory approval and commercialization of the Company’s adult and pediatric Selective Cytopheretic Devices (SCDs). The Company had total assets of $15.5 million and $4.7 million, as of* September 30, 2025* and* December 31, 2024*, respectively.

For segment reporting purposes, the CODM uses operating profit/(loss) to evaluate segment performance and allocate resources. As a Company that only recently began limited commercial sales of QUELIMMUNE, the CODM is primarily focused on evaluating the overall spending for research and development activities needed to fund further development of the SCDs, and general and administrative activities incurred to support the research and development activities of the Company. Accounting policies associated with the Company’s sole segment are the same as those described in Note2.

All of the Company’s sales are located within the United States. As of the date of this report, the Company has obtained regulatory approval for commercial sales in the U.S. of QUELIMMUNE from the FDA. The Company doesnot have any inter-entity sales or transfers.

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The following table represents the Company’s sole segment’s operating results for thenine months ended* September 30, 2025and2024*, respectively(*).

(*) The above table excludes non-operating expenses consisting of interest expense, interest income, and gains and losses from changes in the fair value of liability classified financial instruments such as warrants and convertible debt.

Note15. Subsequent Events

At-the-Market Offering

From* October 1, 2025,through November 13. 2025,*the Company raised approximately $1.2 million in gross proceeds ($1.1 million net of offering costs) from the sale of 1.9 million shares of the Company's stock through its At-the-Market offering program.

Short-Term Note Payable

On* October 28, 2025,the Company entered into a short-term note payable of approximately $0.8 million in order to finance the Company's Directors and Officer's ("D&O") policy for the2025/2026* policy year. The Company has historically financed its D&O policies since* October 2022.*

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