Form S-1MEF Pulmatrix, Inc.

As filed with the Securities and Exchange Commission on April 3, 2019

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

PULMATRIX, INC.

(Exact name of registrant as specified in its charter)

99 Hayden Avenue, Suite 390

Lexington, MA 02421

(781) 357-2333

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Robert W. Clarke, Ph.D.

Chief Executive Officer and President

Pulmatrix, Inc.

99 Hayden Avenue, Suite 390

Lexington, MA 02421

(781) 357-2333

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement is declared effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box:  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☒ 333-230395

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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 to Section 7(a)(2)(B) of the Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

THIS REGISTRATION STATEMENT SHALL BECOME EFFECTIVE UPON FILING WITH THE SECURITIES AND EXCHANGE COMMISSION IN ACCORDANCE WITH RULE 462(B) UNDER THE SECURITIES ACT OF 1933, AS AMENDED.

EXPLANATORY NOTE AND INCORPORATION BY REFERENCE

The Company is filing this registration statement with the Securities and Exchange Commission (the “SEC”) pursuant to Rule 462(b) under the Securities Act of 1933, as amended. This registration statement relates to the public offering of securities contemplated by the Related Registration Statement, as amended, which was originally filed with the SEC on March 19, 2019 and declared effective on April 3, 2019.

We are filing this registration statement for the purpose of registering additional securities of the Company with a proposed maximum aggregate offering price not to exceed $8,144,250. The information set forth in the Related Registration Statement, including all exhibits thereto and all information incorporated by reference therein, is incorporated by reference in this filing.

The required opinions and consents are listed on the exhibit index and filed with this filing.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this Registration Statement on Form S-1 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Lexington, Commonwealth of Massachusetts, on April 3, 2019.

Power of Attorney

Pursuant to the requirements of the Securities Act of 1933, this amendment to the registration statement has been signed by the following persons in the capacities and on the dates indicated.

Exhibit 5.1

[HAYNES AND BOONE, LLP LETTERHEAD]

April 3, 2019

Pulmatrix, Inc.

99 Hayden Ave., Suite 390

Lexington, MA 02421

Ladies and Gentlemen:

We have acted as counsel to Pulmatrix, Inc., a Delaware corporation (the “Company”), in connection with the preparation of the Company’s registration statement on Form S-1 (the “Additional Registration Statement”) filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the “Securities Act”), by the Company with the Securities and Exchange Commission (the “Commission”) on the date hereof, which is related to, and incorporates by reference, the Company’s registration statement on Form S-1 (File No. 333-230395), initially filed on March 19, 2019, as amended (the “Registration Statement”).

The Additional Registration Statement relates to the registration of the proposed offer and sale of (A) a proposed maximum aggregate offering price of $8,144,250 of (i) units (“Common Units”), with each Common Unit being comprised of one share of the Company’s common stock, par value $0.0001 per share (the “Common Stock” and each such share of Common Stock, a “Share” and collectively, the “Shares”) and one common warrant (collectively, the “Common Warrants”) to purchase one share of Common Stock (the shares issuable upon exercise of the Common Warrants, the “Common Warrant Shares”) and (ii) pre-funded units (“Pre-Funded Units” and, together with the Common Units, the “Units”), with each Pre-Funded Unit being comprised of one pre-funded warrant (collectively, the “Pre-Funded Warrants” and, together with the Common Warrants, the “Offering Warrants”) to purchase one share of Common Stock (the shares issuable upon exercise of the Pre-Funded Warrants, the “Pre-Funded Warrant Shares” and, together with the Common Warrant Shares, the “Offering Warrant Shares”) and one Common Warrant, and (B) a proposed maximum aggregate offering price of $224,250 of warrants (the “HCW Warrants” and, together with the Offering Warrants, the “Warrants”) to purchase shares of Common Stock (the “HCW Warrant Shares” and, together with the Offering Warrant Shares, the “Warrant Shares”) to be issued to H.C. Wainwright & Co., LLC (the “Underwriter”) as compensation for its services pursuant to an underwriting agreement to be entered into by and between the Company and the Underwriter, substantially in the form of which to be filed as Exhibit 1.1 to the Registration Statement. The Units, Pre-Funded Units, the Shares, the Warrants and the Warrant Shares are collectively referred to as the “Securities.”

In rendering the opinion set forth herein, we have examined the originals, or photostatic or certified copies, of (i) the Amended and Restated Certificate of Incorporation and Restated Bylaws of the Company, each as amended to date, (ii) certain resolutions of the Board of Directors of the Company related to the filing of the Additional Registration Statement and the Registration Statement, the authorization and issuance of the Securities and related matters, (iii) the Additional Registration Statement and the Registration Statement and all exhibits thereto, (iv) the form of Underwriting Agreement to be entered into with the Underwriter (the “Underwriting Agreement”), (v) a certificate executed by an officer of the Company, dated as of the date hereof, (vi) the forms of the Warrants, and (vii) such other records, documents and instruments as we deemed relevant and necessary for purposes of the opinion stated herein.

Pulmatrix, Inc.

Page 2

In making the foregoing examination we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as photostatic or certified copies, and the authenticity of the originals of such copies. As to all questions of fact material to this opinion, where such facts have not been independently established, we have relied, to the extent we have deemed reasonably appropriate, upon representations or certificates of officers of the Company or governmental officials.

We have not considered, and express no opinion herein as to, the laws of any state or jurisdiction other than the General Corporation Law of the State of Delaware, as currently in effect (the “DGCL”).

Based upon the foregoing, and subject to the qualifications, assumptions, limitations and exceptions stated herein, we are of the opinion that:

Pulmatrix, Inc.

Page 3

The opinions expressed herein as to the validity and legally binding obligation of the Units and the Warrants are subject to and qualified and limited (i) by applicable bankruptcy, insolvency, fraudulent transfer and conveyance, reorganization, moratorium and similar laws affecting creditors’ rights and remedies generally, (ii) as enforceability of any indemnification or contribution provision may be limited under the federal and state securities laws, and (iii) by general principles of equity, including without limitation, concepts of materiality, reasonableness, good faith and fair dealing and the possible unavailability of specific performance or injunctive relief (regardless of whether considered in a proceeding in equity or at law).

We hereby consent to the filing of this opinion with the Commission as an exhibit to the Additional Registration Statement. We further consent to the reference to our firm under the caption “Legal Matters” in the prospectus constituting a part of the Additional Registration Statement. In giving this consent, we are not admitting that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission. This opinion is given as of the date hereof and we assume no obligation to update or supplement such opinion after the date hereof to reflect any facts or circumstances that may thereafter come to our attention or any changes that may thereafter occur.

Very truly yours,

/s/ Haynes and Boone, LLP

HAYNES AND BOONE, LLP

Exhibit 23.1

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM’S CONSENT

We consent to the incorporation by reference in this Registration Statement of Pulmatrix Inc. (the “Company”) on Form S-1 of our report, which includes an explanatory paragraph as to the Company’s ability to continue as a going concern, dated February 19, 2019, with respect to our audits of the consolidated financial statements of Pulmatrix, Inc. as of December 31, 2018 and 2017 and for the years ended December 31, 2018 and 2017, appearing in the Annual Report on Form 10-K of Pulmatrix, Inc. and Subsidiary for the year ended December 31, 2018. We also consent to the reference to our Firm under the heading “Experts” in the Prospectus, which is part of this Registration Statement.

/s/ Marcum LLP

Marcum LLP

New York, NY

April 3, 2019