Pulmatrix, Inc. — Capital/Financing Update 2026

Apr 21, 2026

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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): April 16, 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. ☐

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Item 7.01 Regulation FD Disclosure.

On April 21, 2026, Pulmatrix, Inc. (the “ Company ”) issued a press release announcing the closing of the Private Placement (as defined herein). 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 (the “ Securities Act ”), or the Exchange Act, whether made before or after the date hereof and regardless of any general incorporation language in such filing.

Item 8.01 Other Events

On April 16, 2026, the Company closed its previously announced private placement of its Series B Preferred Stock, par value $0.0001 per share (the “ Private Placement ”). The Private Placement was exempt from the registration requirements of the Securities Act pursuant to the exemption for transactions by an issuer not involving any public offering under Section 4(a)(2) of the Securities Act and Rule 506 of Regulation D of the Securities Act and in reliance on similar exemptions under applicable state laws.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

| Exhibit
No. | Description |
| --- | --- |
| 99.1 | Press Release dated April 21, 2026 (furnished pursuant to Item 7.01) |
| 104 | Cover
Page Interactive Data File (formatted as Inline XBRL) |

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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.

| /s/
Peter Ludlum |
| --- |
| Peter
Ludlum |
| Interim
Chief Executive Officer and Interim Chief Financial Officer |

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