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:

On behalf of our entire Board of Directors, thank you for your continued support of Inogen. I am pleased to invite you to attend the Annual Meeting of Stockholders of Inogen, Inc. (“Inogen” or the "Company"), which will be held on June 5, 2026 at 1:00 p.m. Eastern Time. 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/INGN2026. You will not be able to attend the virtual Annual Meeting physically in person.

Over the recent period, Inogen has undertaken a focused operational and strategic turnaround to strengthen performance and better position the Company for long-term success and value creation. The Board of Directors (the “Board”) and management have advanced initiatives to improve commercial execution, optimize our commercial channels, and enhance operational discipline across the organization, resulting in a return to positive Adjusted EBITDA in 2025. These actions reflect our efforts to address prior challenges while sharpening the Company’s strategic priorities to drive more consistent financial and operational results.

As part of this transformation, Inogen has also taken active steps to strengthen its leadership and governance. This includes the recent appointment of a new independent director whose experience is aligned with the Company’s strategic direction, as well as the addition of key senior management hires to reinforce critical capabilities across the business. Together, these changes are intended to ensure that Inogen has the appropriate leadership, expertise, and oversight to execute its turnaround and deliver sustainable value to stockholders.

Inogen also remains committed to ongoing, constructive engagement with its stockholders. The Board and management team maintain an active dialogue with investors and carefully consider their perspectives in shaping Inogen’s strategy, governance practices, and capital allocation priorities. Consistent with this approach, the Board recently approved a share repurchase program, reflecting its confidence in the Company’s strategy and financial outlook, as well as its commitment to disciplined capital allocation and returning value to stockholders, and has recommended that our stockholders approve a proposal to declassify the Board. This continued engagement underscores Inogen’s focus on accountability and its commitment to aligning its actions with the long-term interests of its stockholders.

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

•

To elect two Class III directors from the nominees described in this proxy statement;

•

To ratify the appointment of Deloitte & Touche LLP as our independent registered public accounting firm for fiscal year ending December 31, 2026;

•

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

•

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

•

To approve an amendment to our Thirteenth Amended and Restated Certificate of Incorporation (the “Charter”) to declassify our Board; and

•

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

Our Board has fixed the close of business on April 6, 2026 as the record date for the Annual Meeting. Only stockholders of record on April 6, 2026 are entitled to notice of and to vote at the Annual Meeting.

The accompanying Notice of Annual Meeting of Stockholders and proxy statement describe the business to be conducted at the Annual Meeting. Also included are a proxy card and postage-paid return envelope. Proxy cards are being solicited on behalf of the Board of Directors of Inogen, Inc.

Your vote is extremely important no matter how many shares you own. Whether or not you plan to attend the virtual Annual Meeting of Stockholders, we urge you to promptly submit your proxy card by mail or vote via the Internet or by telephone.

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

Sincerely,

Kevin R.M. Smith

Chief Executive Officer and President

500 Cummings Center, Suite 2800, Beverly, Massachusetts 01915

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held Virtually on June 5, 2026 at 1:00 p.m. Eastern Time

Important Notice Regarding the Availability of Proxy Materials for the virtual Annual Meeting to Be Held on June 5, 2026. The notice of annual meeting, proxy statement, proxy card, and our annual report to stockholders (the “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

CAUTIONARY NOTE REGARDING Forward-Looking Statements

This proxy statement contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this proxy statement that are not historical facts, including, but not limited to, statements regarding Inogen’s future business plans, market opportunities, financial outlook, growth strategies, and anticipated operational results, are forward-looking statements. Words such as “aims,” “believes,” “anticipates,” “plans,” “expects,” “will,” “intends,” “potential,” “possible,” and similar expressions are intended to identify forward-looking statements. Forward-looking statements are subject to numerous risks and uncertainties that could cause actual results to differ materially from currently anticipated results, including but not limited to, risks and uncertainties relating to Inogen’s 2026 first quarter and full year financial guidance; market acceptance of its products; competition; its sales, marketing and distribution capabilities; its planned sales, marketing, and research and development activities; and risks associated with international operations. Information on these and additional risks, uncertainties, and other information affecting Inogen’s business operating results are contained in its Annual Report on Form 10-K for the period ended December 31, 2025, and in its other filings with the Securities and Exchange Commission ("SEC"). These forward-looking statements speak only as of the date hereof. Inogen disclaims any obligation to update these forward-looking statements except as may be required by law.

TABLE OF CONTENTS

-i-

-ii-

-iii-

500 Cummings Center, Suite 2800

Beverly, Massachusetts 01915

PROXY STATEMENT

FOR 2026 ANNUAL MEETING OF STOCKHOLDERS

To Be Held Virtually on June 5, 2026 at 1:00 p.m. Eastern 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 2026 Annual Meeting of Stockholders, and any postponements, adjournments or continuations thereof (the “Annual Meeting”). The Annual Meeting will be held via live webcast on the Internet at www.virtualshareholdermeeting.com/INGN2026 on Friday, June 5, 2026 at 1:00 p.m. Eastern 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/INGN2026. 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. 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.