UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 2628, 2026

PULMATRIX, INC.

(Exact name of registrant as specified in its charter)

Delaware

001-36199

46-1821392

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

945 Concord Street, Suite 1217

Framingham, MA 01701

(Address of principal executive offices) (Zip Code)

(888) 355-4440

(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐	Pre-commencement communications pursuant to Rule 13e-4 (c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of exchange on which registered
Common Stock, par value $0.0001 per share		PULM		The NASDAQ Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

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 13(a) of the Exchange Act. ☐

Item 21.02 ~~Results~~Termination of ~~Operations~~a ~~and~~Material ~~Financial~~Definitive ~~Condition~~Agreement.

On February 2628, 2026, Pulmatrix, Inc. ~~issued~~(the “Company” or “Pulmatrix”) received a ~~press~~termination notice ~~release~~(the ~~announcing~~“Notice”) ~~its~~from ~~financial~~Cullgen ~~results~~Inc. ~~for~~(“Cullgen”) pursuant to which Cullgen informed the ~~fourth~~Company ~~fiscal~~that ~~quarter~~in accordance with Sections 11.7 and ~~the~~10.1(b) ~~twelve~~of that certain Agreement and Plan of Merger and Reorganization, dated ~~months~~as ~~ended~~of ~~December~~November 3113, ~~2025~~2024, as amended by Amendment No. A1 ~~copy~~thereto dated as of April 7, 2025 (the ~~press~~“Merger ~~release~~Agreement”), by isand ~~furnished~~among asthe ~~Exhibit~~Company, ~~99.1~~Pulmatrix ~~hereto~~and PCL Merger Sub, Inc. and isPCL ~~incorporated~~Merger ~~herein~~Sub byInc. ~~reference~~II, LLC, Cullgen was terminating the Merger Agreement and all related transactions thereunder.

InNeither ~~accordance with General Instruction B.2 of Form 8-K,~~ the ~~information~~Company innor ~~this~~Cullgen ~~Current~~will ~~Report~~be onrequired ~~Form 8-K, including Exhibit 99.1, being furnished pursuant~~ to ~~Item~~pay ~~2.02,~~any ~~shall~~termination ~~not~~fee beas ~~deemed~~a toresult beof ~~“filed” for~~ the ~~purposes~~termination of ~~Section~~the 18Merger ofAgreement. ~~the~~The ~~Securities Exchange~~Company ~~Act~~and ofCullgen ~~1934,~~will aseach ~~amended~~bear ~~(the~~their ~~“Exchange~~respective ~~Act”),~~costs orand ~~otherwise~~expenses ~~subject~~related to the ~~liabilities~~Merger ofAgreement ~~that section,~~ and ~~shall~~the ~~not~~transactions becontemplated ~~incorporated~~thereby byin ~~reference~~accordance ~~into~~with ~~any registration statement or other document filed under~~ the ~~Securities~~terms ~~Act~~ of ~~1933, as amended, or~~ the ~~Exchange~~Merger ~~Act, except as shall be expressly set forth by specific reference in such filing~~Agreement.

Item 7.01 Regulation FD Disclosure.

On March 2, 2026, the Company issued a press release announcing the receipt from Cullgen of the Notice in connection with the Merger Agreement. A copy of the press release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference.

The information in this Current Report on Form 8-K (including Exhibit 99.1 attached hereto) is being furnished pursuant to Item 7.01 and shall not be deemed to be filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise be subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof and regardless of any general incorporation language in such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
99.1		Press Release dated ~~February~~March 262, 2026* (furnished pursuant to Item 7.01)
104		Cover Page Interactive Data File (formatted as Inline XBRL)

* This exhibit is furnished pursuant to Item 2.02 and shall not be deemed to be “filed.”

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	PULMATRIX, INC.
Date: February 26, 2026	By:	/s/ Peter Ludlum
Date: March 2, 2026	By:	/s/ Peter Ludlum
		Peter Ludlum
		Interim Chief Executive Officer and Interim Chief Financial Officer

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