Material Agreement, Financial Obligation, Private Placement (Form 8-K)

Item 1.01 Entry into a Material Definitive Agreement.

On March 6, 2026, CERo Therapeutics Holdings, Inc., a Delaware corporation (the "Company") issued and sold a convertible promissory note for a purchase price of $750,000, having a principal face value of $937,500 (the "Note") to Keystone Capital Partners, LLC ("Lender"). Pursuant to the Note, the Company may borrow, from time to time thereunder, up to a maximum aggregate amount not to exceed a sum of $1,000,000. The Note bears interest at a rate of 10% per annum, matures on August 6, 2027, and is convertible into shares of the Company's common stock, par value $0.0001 per share (the "Common Stock"). At any time after the issuance of the Note, the Lender, at its option, is entitled to convert all or any lesser portion of the outstanding principal amount and accrued but unpaid interest into Common Stock at a conversion price equal to the lesser of (i) $0.05 and (ii) 80% of the average of the 5 (five) lowest intraday trading prices during the 20 (twenty) days prior to the day that the Lender requests conversion, unless otherwise modified by mutual agreement between the parties, subject to certain adjustments and limitations, including a beneficial ownership limitation of 4.99%.

Pursuant to the terms of the Note, the Company shall prepare and file with the U.S. Securities and Exchange Commission (the "SEC"), a registration statement on Form S-1 or S-3, covering the resale of all of the shares of Common Stock issuable upon the conversion of the Note.

The issuance of the Note was made in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended (the "Securities Act"), and Rule 506(b) promulgated thereunder. The Note and the shares of Common Stock issuable upon conversion thereof have not been registered under the Securities Act and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements.

The foregoing description of the Note is qualified in its entirety by reference to the full text of such document, a copy of which was previously filed as Exhibit 4.1 to the Company's Current Report on Form 8-K filed on February 13, 2026 and is incorporated herein by reference.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information set forth under Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 2.03.

Item 3.02 Unregistered Sales of Equity Securities.

The information set forth under Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 3.02. The issuance of the Note was made in reliance on the exemption provided by Section 4(a)(2) of the Securities Act, for the offer and sale of securities not involving a public offering. The Company's reliance upon Section 4(a)(2) of the Securities Act in issuing the Note was based upon the following factors: (a) the issuance of the Note was an isolated private transaction by us which did not involve a public offering; (b) the Lender is an accredited investor; (c) the Company did not engage in general solicitation or advertising in connection with the issuance; and (d) the Lender represented that, among other things, it was acquiring the securities for investment purposes only and not with a view to distribution, it has received information about the Company necessary to make an informed investment decision, and the Lender is capable of evaluating the merits and risks of its investment. Any shares of Common Stock issuable upon conversion of the Note will be issued in reliance on the exemption from registration provided by Section 3(a)(9) or Section 4(a)(2) of the Securities Act.