Inogen Inc

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

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

 Definitive Additional Materials

 Soliciting Material Pursuant to §240.14a-12

Inogen, Inc.

(Name of Registrant as Specified In Its Charter)

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

 No fee required.

 Fee paid previously with preliminary materials

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

Dear Stockholder:

I am pleased to invite you to attend the Annual Meeting of Stockholders of Inogen, Inc. (“Inogen”), which will be held on May 14, 2025 at 10:00 a.m. Pacific Time as a virtual meeting. The Annual Meeting of Stockholders (together with any postponements, adjournments or continuations thereof, the “Annual Meeting”) will be held in a virtual meeting format only. You will be able to attend the meeting, vote and submit your questions via the Internet atwww.virtualshareholdermeeting.com/INGN2025. You will not be able to attend the virtual Annual Meeting physically in person.

At the Annual Meeting, we will ask you to consider the following proposals:

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To elect three Class II directors from the nominees described in this proxy statement;

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To ratify the appointment of Deloitte & Touche LLP as our independent registered public accounting firm for fiscal year ending December 31, 2025;

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To approve, on an advisory and non-binding basis, the compensation of our named executive officers as described in this proxy statement;

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To approve the Inogen, Inc. Amended and Restated 2023 Equity Incentive Plan; and

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To transact such other business as may properly come before the Annual Meeting or any adjournments or postponements thereof.

Our Board of Directors has fixed the close of business on March 17, 2025 as the record date for the Annual Meeting. Only stockholders of record on March 17, 2025 are entitled to notice of and to vote at the Annual Meeting. Further information regarding voting rights and the matters to be voted upon is presented in the accompanying proxy statement.

We are pleased to be furnishing proxy materials to stockholders primarily over the Internet for our Annual Meeting. Consequently, most stockholders will not receive paper copies of our proxy materials. We will instead send to our stockholders a Notice of Internet Availability of Proxy Materials. We believe that this process expedites stockholders’ receipt of proxy materials, lowers the costs of our Annual Meeting, and conserves natural resources.

On or about March 27, 2025, we expect to mail to our stockholders a Notice of Internet Availability of Proxy Materials containing instructions on how to access our proxy statement for our Annual Meeting and our 2024 annual report to stockholders (“Annual Report”). The Notice of Internet Availability of Proxy Materials also includes instructions on how you can vote using the Internet and how you can request and receive, free of charge, a printed copy of our proxy materials. Our proxy statement and our Annual Report can be accessed directly at the following Internet address: http://www.proxyvote.com by entering the control number located on your proxy card. All stockholders who do not receive a Notice of Internet Availability of Proxy Materials will receive a paper copy of the proxy materials by mail.

YOUR VOTE IS IMPORTANT. Whether or not you plan to attend the virtual Annual Meeting of Stockholders, we urge you to submit your vote via the Internet, telephone or mail.

On behalf of the Board of Directors, I would like to express our appreciation for your interest in Inogen.

Sincerely,

Kevin R.M. Smith

Chief Executive Officer and President

The Notice of Internet Availability of Proxy Materials is first being mailed to our stockholders on or about March 27, 2025. The proxy materials are first being posted onhttp://www.proxyvote.com on or about March 27, 2025.

INOGEN, INC.

859 Ward Drive, Suite 200, Goleta, California 93111

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held Virtually on May 14, 2025 at 10:00 a.m. Pacific Time

Important Notice Regarding the Availability of Proxy Materials for the virtual Annual Meeting to Be Held on May 14, 2025. The notice of annual meeting, proxy statement, proxy card, and Annual Report are available by visiting http://www.proxyvote.com. All you have to do is enter the control number located on your proxy card.

By order of the Board of Directors,

Kevin P. Smith

General Counsel and Executive Vice President, Business Development

The Notice of Internet Availability of Proxy Materials is first being mailed to our stockholders on or about March 27, 2025. The proxy materials are first being posted onhttp://www.proxyvote.com on or about March 27, 2025.

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INOGEN, INC.

859 Ward Drive, Suite 200

Goleta, California 93111

PROXY STATEMENT

FOR 2025 ANNUAL MEETING OF STOCKHOLDERS

To Be Held Virtually on May 14, 2025 at 10:00 a.m. Pacific Time

This proxy statement and the accompanying form of proxy are furnished in connection with the solicitation of proxies by our Board of Directors (the “Board”) of Inogen, Inc. (“Inogen” or the “Company”) for use at our 2025 Annual Meeting of Stockholders, and any postponements, adjournments or continuations thereof (the “Annual Meeting”). The Annual Meeting will be held virtually via live webcast on the Internet at www.virtualshareholdermeeting.com/INGN2025 on Wednesday, May 14, 2025 at 10:00 a.m. Pacific Time in a virtual meeting format only. You will not be able to attend the Annual Meeting physically in person. The live webcast of the Annual Meeting can be accessed by stockholders on the day of the meeting at www.virtualshareholdermeeting.com/INGN2025. If you have difficulty accessing the virtual meeting during the check-in or meeting time, a technical assistance phone number will be made available on the virtual meeting registration page 15 minutes prior to the start time of the meeting. On or about March 27, 2025, we expect to mail to our stockholders a Notice of Internet Availability of Proxy Materials (the “Notice”) containing instructions on how to access our proxy statement for our Annual Meeting and our annual report to stockholders (“Annual Report”). Information contained on, or that can be accessed through, our website is not intended to be incorporated by reference into this proxy statement and references to our website address in this proxy statement are inactive textual references only.