8-K/A

UNITEDSTATES

SECURITIESAND EXCHANGE COMMISSION

WASHINGTON,D.C. 20549

FORM8-K/A

(AmendmentNo. 1)

CURRENTREPORT

Pursuantto Section 13 or 15(d) of the

SecuritiesExchange Act of 1934

Dateof Report (Date of earliest event reported): June 17, 2020

PULMATRIX,INC.

(Exactname of registrant as specified in its charter)

99Hayden Avenue, Suite 390

Lexington,MA 02421

(Addressof principal executive offices) (Zip Code)

(781)357-2333

(Registrant’stelephone number, including area code)

N/A

(Formername 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:

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

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. [  ]

ExplanatoryNote

This Current Report on Form 8-K/A (this “Amendment”) amends the Current Report on Form 8-K of Pulmatrix, Inc. (the “Company”) filed with the U.S. Securities and Exchange Commission on June 19, 2020 (the “Original Form 8-K”). The Original Form 8-K reported the final voting results of the Company’s 2020 Annual Meeting of Stockholders held on June 17, 2020 (the “2020 Annual Meeting”). The sole purpose of this Amendment is to disclose the Company’s decision regarding how frequently it will conduct future stockholder advisory votes to approve the compensation of the Company’s named executive officers (“Say-on-Pay Vote(s)”). No other changes have been made to the Original Form 8-K.

Item 5.07 Submission of Matters to a Vote of Security Holders.

As previously reported in the Original Form 8-K, in an advisory vote held at the 2020 Annual Meeting on the frequency of future Say-on-Pay Votes, the Company’s stockholders expressed their preference for a Say-on-Pay Vote to be conducted every three years. On November 10, 2020, the Company’s board of directors considered the outcome of this advisory vote and determined that future Say-on-Pay Votes will be conducted every three years. The Company’s board of directors will re-evaluate this determination after the next stockholder advisory vote on the frequency of Say-on-Pay Votes (which will be at the 2026 Annual Meeting of Stockholders, unless presented earlier).

SIGNATURES

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