UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.                      )

Filed by the Registrant x

Filed by a Party other than the Registrant ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

x Definitive Additional Materials

¨ Soliciting Material under §240.14a-12

ARMATA PHARMACEUTICALS, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant) 

Payment of Filing Fee (Check the appropriate box):

x No fee required.

¨ Fee paid previously with preliminary materials.

¨ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a6(i)(1) and 0-11.

Step 1: Go to www.envisionreports.com/ARMP. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. www.envisionreports.com/ARMP Online Go to www.envisionreports.com/ARMP or scan the QR code — login details are located in the shaded bar below. Shareholder Meeting Notice 03UX2A + + Important Notice Regarding the Availability of Proxy Materials for the Armata Pharmaceuticals, Inc. Shareholder Meeting to be Held on September 14, 2023. Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual shareholders’ meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The Notice of Proxy Statement and Annual Report to shareholders are available at: Obtaining a Copy of the Proxy Materials – If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before September 1, 2023 to facilitate timely delivery. 2NOT Easy Online Access — View your proxy materials and vote. When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Votes submitted electronically must be received by 11:59 p.m., local time, on September 13, 2023 Step 4: Make your selections as instructed on each screen for your delivery preferences. Step 5: Vote your shares.

Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. — Internet – Go to www.envisionreports.com/ARMP. Click Cast Your Vote or Request Materials. — Phone – Call us free of charge at 1-866-641-4276. — Email – Send an email to investorvote@computershare.com with “Proxy Materials Armata Pharmaceuticals, Inc.” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, all requests for a paper copy of proxy materials must be received by September 1, 2023. Armata Pharmaceuticals, Inc. Annual Meeting of Shareholders will be held on September 14, 2023, 8:30am PT, at 5005 McConnell Avenue, Los Angeles, CA 90066. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommends a vote FOR all nominees and FOR Proposals 2, 3, and 4: 1. Election of Directors: 01 - Jules Haimovitz 02 - Odysseas Kostas 03 - Robin Kramer 04 - Joseph Patti 05 - Todd Peterson 06 - Sarah Schlesinger 07 - Deborah Birx 2. To approve, on an advisory, non-binding basis, the compensation of our named executive officers 3. To ratify the Audit Committee’s selection of Ernst & Young, LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2023 4. To approve, in accordance with the NYSE American exchange rules, the issuance of shares of the Company’s common stock, par value $0.01 per share, upon conversion, if applicable, of the loan outstanding under the Secured Convertible Credit and Security Agreement with Innoviva Strategic Opportunities LLC 5. To conduct any other business properly brought before the meeting or any adjournment or postponement thereof PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please bring this notice with you. Shareholder Meeting Notice