HCW Biologics Inc.

10b5-1 Trading Plans

During the fiscal quarter ended December 31, 2025, none of our officers or directors adopted orterminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.

Special Meeting of Stockholders

As required in the $1.5 million equity offering and repricing of existing warrants that closed on February 19, 2026, the Company will hold a Special Meeting of Stockholders on April 27, 2026 at 10:00 a.m. Eastern Time. At the Special Meeting the Company will submit the following two proposals to its stockholders for approval:

Proposal 1:

To approve, for purposes of complying with Nasdaq Listing Rule 5635(d), the issuance of shares of our Common Stock upon exercise of up to 2,477,292 Common Stock Purchase Warrants (the “Common Warrants”) issued pursuant to that certain Securities Purchase Agreement, dated February 17, 2026 (the “SPA”), entered into in connection with the Company’s follow-on public offering of Units (the “Offering”), which Offering was conducted pursuant to a registration statement (the “Registration Statement”) declared effective by the SEC on February 17, 2026 and closed on February 19, 2026, as previously disclosed in the Company’s Current Report on Form 8-K filed on February 19, 2026, each Unit consisting of (i) one share of Common Stock or one Pre-Funded Warrant to purchase one share of Common Stock and (ii) one Common Warrant, with such Common Warrants exercisable only upon receipt of stockholder approval and having an exercise price equal to 100% of the public offering price per Unit, and such additional terms and conditions of the Common Warrants not materially inconsistent with the foregoing as our Board may hereafter approve;

Proposal 2:

To approve, for purposes of complying with Nasdaq Listing Rule 5635(d), the repricing of certain warrants issued on November 20, 2025 to purchase up to 3,020,410 shares of our Common Stock (the “Prior Warrants”) pursuant to that certain Existing Warrants Amendment Agreement, dated February 17, 2026, entered into in connection with the Offering conducted pursuant to the Registration Statement (as disclosed in the Company’s Current Report on Form 8-K filed on February 19, 2026), to reduce the exercise price of the Prior Warrants from $2.41 per share to $0.6055 per share, and to approve the issuance of shares of our Common Stock upon exercise of the Prior Warrants as so amended, and such additional terms and conditions of such amendment not materially inconsistent with the foregoing as our Board may hereafter approve; and

Proposal 3:

To transact such other business as may properly come before the Special Meeting or any adjournments or postponements thereof.

Standby Equity Line of Credit

On February 20, 2025, the Company entered into an equity purchase agreement (the “ELOC Purchase Agreement”) with Square Gate Capital Master Fund, LLC – Series 4 (“Square Gate”) pursuant to which, upon the terms and subject to the conditions and limitations set forth therein, the Company has the right to direct Square Gate to purchase up to an aggregate of $20,000,000 of shares of our Common Stock, plus, at the Company’s option upon utilizing the initial $20,000,000, an additional amount equal to the lesser of 100% of the Company’s market capitalization at the time of exercise of such option or $20,000,000, over the 36-month term of the ELOC Purchase Agreement. The Company issued 9,616 shares of our Common Stock to Square Gate on March 12, 2025, as its Commitment Fee under the ELOC Purchase Agreement (the “Commitment Shares”). On April 16, 2025, the SEC declared a registration statement effective to register the Commitment Shares and shares required to sell up to $40.0 million of the Company’s shares to Square Gate, according to provisions of the Equity Purchase Agreement.

February 2026 Financing

On February 17, 2026, the Company entered into a securities purchase agreement with a single institutional investor (the “Investor”) pursuant to which the Company agreed to offer and sell, in a follow-on public offering (the “2026 Offering”), 2,477,292 units (the “Units”) consisting of (i) 2,477,292 shares (the “Common Shares”) of the Company’s Common Stock, $0.0001 par value per share (the “Common Stock”) or, in lieu thereof, up to 2,477,292 Pre-Funded Warrants (as defined below) to purchase up to 2,477,292 shares of Common Stock (the “Pre-Funded Warrant Shares”), and (ii) up to 2,477,292 Common Stock purchase warrants the exercise of which is conditioned on stockholder approval (the “Common Warrants”, and together with the Pre-Funded Warrants, the “Warrants”) to purchase up to 2,477,292 shares of Common Stock.

On February 17, 2026, the Company also entered into a privately negotiated agreement with the Investor, which holds certain existing outstanding warrants to purchase up to 3,020,410 shares of Common Stock (the “Prior Warrants”) to seek stockholder approval in accordance with applicable Nasdaq rules to reduce the exercise price of such Prior Warrants to the public offering price per Unit paid in the Offering (the “Existing Warrants Amendment Agreement”). There can be no assurance that we will obtain such stockholder approval or amend the Prior Warrants or as to the final terms of any amendments to the Prior Warrants.

The combined purchase price for each Unit consisting of one share of Common Stock or Pre-Funded Warrant in lieu thereof and accompanying Common Stock Warrant to purchase one share of Common Stock was $0.6055 per unit, and the combined purchase price for each unit consisting of one Pre-Funded Warrant that may be exercised for one share of Common Stock and accompanying Common Stock Warrant to purchase one share of Common Stock is $0.6054. The Common Stock Warrants have an exercise price of $0.6055 per share, will be exercisable only upon receipt of stockholder approval thereof in accordance with applicable Nasdaq rules, and expire on the five-year anniversary of such stockholder approval. The Pre-Funded Warrants have an exercise price of $0.0001, are exercisable immediately and will not expire until exercised in full.

The securities described above were offered pursuant to a registration statement on Form S-1, as amended (File No. 333-293396), which was declared effective by the Securities and Exchange Commission (the “SEC”) on February 17, 2026. The gross proceeds to the Company from the 2026 Offering are approximately $1.5 million before deducting the placement agent’s fees and other offering expenses payable by the Company. The 2026 Offering closed on February 19, 2026.

On February 17, 2026, the Company entered into a placement agency agreement (the “Placement Agency Agreement”) with Maxim Group LLC (“Maxim” or the “Placement Agent”) pursuant to which the Company engaged the Placement Agent as the exclusive placement agent in connection with the Offering. The Company agreed to pay the Placement Agent a cash fee equal to 6.9% of gross proceeds from the sale of Common Shares, Pre-Funded Warrants and Common Stock Warrants to the Investor. The Company also agreed to reimburse the Placement Agent for out-of-pocket expenses, including the reasonable legal fees of its counsel not to exceed $65,000. The Placement Agency Agreement also contains representations, warranties, indemnification and other provisions customary for transactions of this nature.

On March 16, 2026, the Investor exercised all of the Pre-Funded Warrants purchased in this transaction, and the Company issued 2,477,292 shares of Common Stock.

May 2025 Financing

On May 13, 2025, the Company entered into a securities purchase agreement with a single institutional investor (the “Investor”) for the issuance and sale of (i) 158,000 shares (the “Shares”) of the Company’s Common Stock and (ii) Pre-funded Warrants to purchase up to 513,140 shares of Common Stock (the “Pre-Funded Warrants”) in a follow-on public offering (the “Offering”), pursuant to a registration statement filed under Rule 424(b)(4) (File No. 333-287136), which was declared effective by the SEC on May 15, 2025. The Company also issued warrants to purchase up to an aggregate of 1,342,280 shares of Common Stock (“Common Stock Warrants”) for $7.45 per share.

The Company sold the Common Stock and Pre-Funded Warrants with an accompanying two Common Stock Warrant, each of which may purchase one share of Common Stock, and the Common Stock and Pre-Funded Warrants were immediately separated from the Common Stock Warrants and issued separately. The combined purchase price for each Share and the two accompanying Common Stock Warrant was $7.45 per unit and the combined purchase price for each Pre-Funded Warrant and the two accompanying Common Stock Warrant was $7.4999 per unit. The Common Stock Warrants have an exercise price of $7.45 per share, are exercisable immediately, and expire on the five-year anniversary of the date of issuance. The Pre-Funded Warrants have an exercise price of $0.0001 per share, are exercisable immediately, and will not expire until exercised in full.

The gross proceeds to the Company from the Offering were approximately $5.0 million before deducting the placement agent’s fees and other offering expenses of $802,602 payable by the Company. In this financing, the Company issued shares of Common Stock of Pre-Funded Warrants that may be exercised to purchase Common Stock in lieu thereof, and warrants that may be exercised to purchase Common Stock. In a contemporaneous private agreement entered into with the Investor, the Company agreed to reprice warrants to purchase up to 167,925 shares of Common Stock that were issued to the Investor in a financing that closed on November 20, 2024 to an exercise price of $7.45 per share. The fair value of the securities issued in this transaction was $15.2 million. This included a fair value of $1.3 million for the shares of Common Stock issued based on the number of shares issued times the closing price on May 15, 2025, or $8.20 per share. In addition, the fair value of the warrants issued in this transaction was estimated at $13.9 million using the Black-Scholes option pricing model with assumptions including a term of 5 - 10 years, volatility of 120.6% and a risk-free rate of 4.07% - 4.45% As this was a transaction with an existing stockholder, the difference between the gross proceeds and the fair value of securities issued, or $10.2 million, was deemed to be an equity dividend to the Investor which was recorded in additional-paid-in capital as of September 30, 2025.

The Investor may not exercise any portion of the Common Stock Warrants or Pre-Funded Warrants to the extent it would beneficially own more than the limits defined in the respective Warrant Purchase Agreement. The exercise price and number of shares of Common Stock issuable upon the exercise of the Common Stock Warrants and Pre-Funded Warrants are subject to adjustment in the event of any stock dividends and distributions, stock splits, stock combinations or stock reclassifications, as described in the respective warrant agreements. Under certain circumstances, the warrants may be exercised on a “cashless” basis.

Both the Common Stock Warrants and Pre-Funded Warrants were classified as a component of permanent stockholders’ equity within additional paid-in-capital and were recorded at the issuance date. The Common Stock Warrants and Pre-Funded Warrants are equity classified because they are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, permit the holders to receive a fixed number of shares of Common Stock upon exercise, are indexed to the Company’s Common Stock and meet the equity classification criteria. In addition, the Common Stock Warrants and the Pre-Funded Warrants do not provide any guarantee of value or return.

As of December 31, 2025, the Investor exercised all of the Pre-Funded Warrants by delivering a notice of exercise to the Company and paying the exercise price. As a result, the Company issued 513,140 shares of registered Common Stock to the Investor as of December 31, 2025.

The Common Stock Warrants issued in May 2025 were repriced and exercised in the Inducement Transaction on November 19, 2025 (see below).

November 2024 Financing

On November 18, 2024, the Company entered into a securities purchase agreement with a single institutional investor (the “Investor”) pursuant to which the Company agreed to offer and sell (i) in a registered direct offering (the “Registered Offering”) (x) 104,000 shares (the “Shares”) of the Company’s Common Stock, par value $0.0001 per share (the “Common Stock”), and (y) Pre-funded Warrants to purchase up to 63,925 shares of Common Stock (the “Pre-Funded Warrants”) and (ii) in a concurrent private placement (the “Private Placement” and together with the Registered Offering, the “Offering”), unregistered warrants to purchase up to an aggregate of 154,275 shares of Common Stock (“Armistice Warrants”). The combined purchase price for each Share and accompanying Armistice Warrant to purchase one share of Common Stock was $41.20 per Share and the combined purchase price for each Pre-Funded Warrant and accompanying Common Stock Warrant to purchase one share of Common Stock was $40.196.

The Common Stock and Pre-Funded Warrants were each sold with an accompanying Armistice Warrant to purchase one share of Common Stock, and the Common Stock and Pre-Funded Warrants were immediately separated from the Armistice Warrants and were issued separately. The Armistice Warrants have an exercise price of $41.20 per share, are exercisable immediately, and expire on the five year anniversary of the date of issuance. The Pre-Funded Warrants have an exercise price of $0.0001, are exercisable immediately and will not expire until exercised in full.

The shares of Common Stock and Pre-Funded Warrants in the Registered Offering were offered pursuant to a shelf registration statement on Form S-3 (File No. 333-266991), which was declared effective by the SEC on August 26, 2022. The Registered Offering has been made by means of a prospectus supplement filed with the SEC on November 20, 2024 that forms a part of such registration statement.

The gross proceeds to the Company from the Registered Offering were approximately $6.9 million before deducting the placement agent’s fees and other offering expenses payable by the Company. The Offering closed on November 20, 2024.

The Common Stock Warrants issued in November 2024 were repriced and exercised in the Inducement Transaction on November 19, 2025 (see below).

Conversion of Unsecured Convertible Promissory Notes

As of May 5, 2025, the Company issued a total of $270,000 principal amount of unsecured convertible promissory notes that mature on May 5, 2026 with paid in kind interest accruing thereon, payable quarterly in arrears at 10% per annum. In accordance with their terms, following the completion of a qualified offering, these notes were converted into shares of our Common Stock at the final offering price in an offering that closed on May 15, 2025. In addition, holders of the unsecured convertible promissory notes have the right to receive a portion of the proceeds of the Company’s shares of Wugen common stock, if and when such shares are ever sold, determined by the number of the Wugen shares equal to 0.25 multiplied by the original principal amount, in dollars, of these notes. Investors included: $60,000 invested by Hing C. Wong, the Company’s Founder and CEO; $100,000 invested by Scott T. Garrett, the Chairman of the Company’s Board of Directors; and $10,000 invested by Gary M. Winer, who was a member of the Company’s Board of Directors at the time of his investment.

As of May 15, 2025, the outstanding principal of unsecured convertible promissory notes were converted. The fair value of consideration transferred including 36,242 shares of Common Stock and rights to proceeds of a portion of the Company’s shares of Wugen common stock was $401,134, with the difference of $131,135 being recognized as a loss on conversion. Due to the related party nature of the converting noteholders, the loss was recorded to additional paid-in capital in the accompanying audited financial statements as of and for the year ended December 31, 2025.

Conversion of Secured Notes

The holders of $6.6 million of the outstanding principal of the Secured Notes have agreed to and effected the conversion of the Secured Notes held by them into shares of the Company’s Common Stock at a conversion price of $26.00 per share (“Conversion Shares”), warrants to purchase approximately $3.3 million of the Company’s Common Stock at an exercise price of $26.00 per share (“Conversion Warrants”), and the right to their pro rata share of 49.11% of the proceeds of the Company’s shares of Wugen common stock (“Wugen Shares”), if and when such shares are ever sold (the “Wugen Proceeds”). The conversion was approved at a Special Meeting of Stockholders held on March 31, 2025 and was effected pursuant to the terms of the Conversion Amendment. On May 7, 2025, pursuant to the Conversion Amendment, the Secured Notes held by the participating noteholders were cancelled, and the Company issued a total of 253,083 unregistered shares of Common Stock (which are subject to a 180-day lock-up) and warrants to purchase an additional 126,540 shares of Common Stock at an exercise price of $26.00 per share. On January 29, 2026, the SEC declared effective a resale registration statement on Form S-1 (File Number 333-292652) covering the resale of shares of Common Stock and warrants issued to such note holders.

Inducement Agreement

On November 19, 2025, the Company entered into a warrant inducement agreement with a single institutional investor who is an existing stockholder of the Company (the “Inducement Agreement”), pursuant to which the Investor agreed to immediately exercise in full all of its outstanding warrants originally issued on November 20, 2024 (as amended on May 15, 2025) and on May 15, 2025 (the “Existing Warrants”) to purchase an aggregate of 1,510,205 shares of Common Stock at an amended exercise price of $2.66 per share, resulting in aggregate gross proceeds to the Company of approximately $4.0 million before fees and expenses. In consideration for the immediate exercise of the Existing Warrants, the Company issued to the Investor, in a private placement pursuant to Section 4(a)(2) of the Securities Act, new unregistered Common Stock Purchase Warrants (the “New Warrants”) to purchase up to 3,020,410 shares of Common Stock at an exercise price of $2.41 per share. The New Warrants are exercisable immediately and expire five and one-half years from their issuance. The New Warrants and the shares of Common Stock issuable upon their exercise have not been registered under the Securities Act. The Company agreed, pursuant to the Inducement Agreement, to file a registration statement covering the resale of the shares issuable upon exercise of the New Warrants. Maxim Group LLC acted as a financial advisor in connection with this November 19, 2025 warrant inducement. On January 29, 2026, the SEC declared effective a resale registration statement on Form S-1 (File Number 333-292652) covering the resale of shares of Common Stock underlying the New Warrants.

As of December 31, 2025, there were 977,000 shares held in abeyance. On February 25, 2026 and March 16, 2026, the Investor requested the Company issue 237,000 and 740,000, respectively, of the remaining shares in abeyance.

Sale of Common Stock in Private Placement

On February 20, 2024, we entered into subscription agreements (the “Subscription Agreements”) with certain officers and directors of the Company, including our Founder and Chief Executive Officer, our Chief Financial Officer and the Chairman of the Company’s Board of Directors, pursuant to which the Company sold an aggregate of 44,643 shares of our Common Stock, at a purchase price of $56.00 per share for an aggregate purchase price of $2.5 million. The per share purchase price represents a 25% premium to the per share closing price of the Common Stock as reported on the Nasdaq Global Market on the February 20, 2024 and a 19% premium to the 5-day volume weighted average closing price per share of the Common Stock as reported on the Nasdaq Global Market for the period ending on the February 20, 2024.

The shares of Common Stock issued pursuant to the Subscription Agreements were not registered under the Securities Act of 1933, as amended, in reliance upon exemptions under Section 4(a)(2) of the Securities Act of 1933, as amended.