ASPEN AEROGELS 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:

(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 all boxes that apply):

Northborough, Massachusetts

March 17, 2025

Dear Aspen Aerogels, Inc. Stockholder:

You are cordially invited to attend the 2025 annual meeting of stockholders of Aspen Aerogels, Inc. to be held at 9:30 a.m. Eastern Time on Wednesday, April 30, 2025. This year’s annual meeting will be conducted solely via live audio webcast on the Internet.

You will be able to attend our annual meeting, vote and submit your questions during the annual meeting by visiting www.virtualshareholdermeeting.com/ASPN2025. You will not be able to attend the annual meeting in person.

Details regarding the meeting, the business to be conducted at the meeting, and information about Aspen Aerogels that you should consider when you vote your shares are described in the accompanying proxy statement.

At the 2025 annual meeting, two persons will be elected to our Board of Directors. In addition, we ask stockholders to ratify the appointment of KPMG LLP as our independent registered public accounting firm for our fiscal year ending December 31, 2025, to approve, on a non-binding, advisory basis, the compensation of the named executive officers, as disclosed in the accompanying proxy statement for the 2025 annual meeting of stockholders, to approve the Aspen Aerogels Amended and Restated 2023 Equity Incentive Plan, and to approve the Aspen Aerogels Employee Stock Purchase Plan. Our Board of Directors recommends the election of the two nominees to our Board of Directors and a vote in favor of proposals (2), (3), (4) and (5). Such other business will be transacted as may properly come before the annual meeting.

Under Securities and Exchange Commission rules that allow companies to furnish proxy materials to stockholders over the Internet, we have elected to deliver our proxy materials to the majority of our stockholders over the Internet. This delivery process allows us to provide stockholders with the information they need, while at the same time conserving natural resources and lowering the cost of delivery. On or about March 17, 2025, we will send to our stockholders a Notice of Internet Availability of Proxy Materials (the “Notice”) containing instructions on how to access our proxy statement for our 2025 annual meeting of stockholders and our 2024 annual report to stockholders. The Notice also provides instructions on how to vote online and includes instructions on how to receive a paper copy of the proxy materials by mail.

We hope you will be able to attend the annual meeting. Whether you plan to attend the annual meeting or not, it is important that you cast your vote. Prior to the annual meeting, you may vote by proxy over the Internet as well as by telephone or by mail. When you have finished reading the proxy statement, you are urged to vote in accordance with the instructions set forth in the proxy statement. We encourage you to vote by proxy so that your shares will be represented and voted at the meeting, whether or not you can attend. Any stockholder attending the virtual annual meeting may vote online during the annual meeting, even if you already returned a proxy card or voted by proxy over the telephone or the Internet.

Thank you for your continued support of Aspen Aerogels, Inc. We look forward to seeing you at the annual meeting.

Sincerely,

Donald R. Young

President and Chief Executive Officer

NOTICE OF 2025 ANNUAL MEETING OF STOCKHOLDERS

TIME: 9:30 a.m. Eastern Time

DATE: Wednesday, April 30, 2025

ACCESS: www.virtualshareholdermeeting.com/ASPN2025

This year’s annual meeting will be a virtual meeting via live webcast on the Internet. You will be able to attend the annual meeting, vote and submit your questions during the meeting by visiting www.virtualshareholdermeeting.com/ASPN2025 and providing relevant information, including the control number included in the Notice of Internet Availability or the proxy card or voting instruction form that you received. For further information, please see the Important Information About the Annual Meeting and Voting beginning on page 4 of this proxy statement.

PURPOSES:

To elect Kathleen M. Kool and William P. Noglows as directors to serve three-year terms expiring in 2028;

To ratify the appointment of KPMG LLP as Aspen Aerogels, Inc.’s independent registered public accounting firm for the fiscal year ending December 31, 2025;

To approve, on a non-binding, advisory basis, the compensation of the named executive officers, as disclosed in our proxy statement for the annual meeting;

To approve the Aspen Aerogels Amended and Restated 2023 Equity Incentive Plan;

To approve the Aspen Aerogels Employee Stock Purchase Plan; and

To transact such other business that is properly presented at the annual meeting and any adjournments or postponements thereof.

WHO MAY VOTE:

You may vote if you were the record owner of Aspen Aerogels, Inc.’s common stock at the close of business on March 10, 2025 (the “Record Date”). A list of registered stockholders as of the close of business on the Record Date will be available at our corporate headquarters for examination by any stockholder for any purpose germane to the annual meeting for a period of 10 days ending on the day before the date of the annual meeting. If you wish to view this list, please contact our Corporate Secretary at Aspen Aerogels, Inc., 30 Forbes Road, Building B, Northborough, Massachusetts 01532.

All stockholders are cordially invited to attend the virtual annual meeting. Whether you plan to attend the annual meeting or not, we urge you to vote by following the instructions in the Notice of Internet Availability of Proxy Materials or proxy materials you received and submit your proxy by the Internet, telephone or mail in order to ensure the presence of a quorum. You may change or revoke your proxy at any time before it is voted at the meeting.

By Order of the Board of Directors,

Virginia H. Johnson

Chief Legal Officer, General Counsel & Corporate Secretary

Northborough, Massachusetts

March 17, 2025

CREATING VALUE THROUGH TECHNOLOGY, INNOVATION, AND EXECUTION

Dear Stakeholders,

In 2024, we continued to drive profitable growth across both our Thermal Barrier and Energy Industrial businesses, achieving record-breaking consolidated revenue of $452.7 million. More significantly, we expanded gross profit margins from 24% in 2023 to 40% in 2024 and delivered positive net income for the year.

Our PyroThin® thermal barrier business achieved record annual revenues, reaching an impressive $307 million for the year – a remarkable 179% year-over-year increase. We also made significant strides in diversifying our customer base, securing contracts with three additional major automotive OEMs, bringing our total number of global automotive OEM customers to eight.

Our Energy Industrial business also delivered outstanding results, generating $146 million in revenue with gross margins exceeding our 35% long-term target. With the successful transition to our external manufacturing facility, this segment is now well-positioned to meet the growing global demand for our products.

Meanwhile, we remain focused on diversifying our business over the long term by continuing to advance our strategy of leveraging our Aerogel Technology Platform® into new and dynamic markets, expanding its applications to drive innovation and create new growth opportunities.

These achievements underscore the successful execution of our multi-year strategy to build a resilient and profitable business. They position us well for continued success in 2025 and beyond, delivering value to all stakeholders—employees, customers, suppliers, communities, and investors alike.

2024 Highlights and Recent Business Developments

In 2024, we remained focused on accelerating revenue growth across our core business segments, optimizing productivity and operational efficiency, exercising disciplined cost management, and increasing flexibility of our aerogel supply. At the same time, we strengthened our balance sheet, reduced our capital expenditure plans, and optimized our cost of capital to position the company to drive sustainable profitability and long-term shareholder value:

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Grew record consolidated revenue 90% year-over-year to $452.7 million.

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Generated record PyroThin thermal barrier revenue of $306.8 million, up 179% year-over-year.

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Delivered Energy Industrial revenue of $145.9 million, up 13% year-over-year, including over $112 million of supply from our external manufacturing facility.

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Recorded 2024 gross margins of 40%, which drove $13.4 million of Net Income and $89.9 million of Adjusted EBITDA.

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Awarded PyroThin contract from a major EU luxury sports car OEM. The vehicle platform is expected to underpin multiple nameplates and has an expected start of production in 2025.

•

Secured additional PyroThin award from The Automotive Cells Company (“ACC”), a battery cell joint-venture between Stellantis N.V., Saft-TotalEnergies, and Mercedes-Benz, to supply PyroThin Thermal Barriers to Mercedes-Benz for its battery electric platform based on prismatic cells with production expected to begin in 2027.

•

Awarded a contract to supply PyroThin Thermal Barriers for a Volvo Truck commercial vehicle program.

•

Closed on $125 million term loan facility and $100 million capacity asset-based revolving credit facility with MidCap Financial, a leading commercial finance company managed by Apollo Capital Management, L.P. The proceeds from this transaction were utilized for the full cash redemption of the Company's legacy convertible note and for general corporate purposes.

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Ended the year with cash and equivalents of $220.9 million and believe that we are fully funded to execute our current strategy and explore opportunistic uses of capital.

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Won a coveted Automotive News PACE Award for PyroThin platform used by leading automotive OEMs globally to improve electric vehicle EV battery safety and performance. Aspen was also honored with an Innovation Partnership Award recognizing its extensive collaboration with General Motors in relation to the selection of PyroThin as the thermal runaway solution for its Ultium battery platform. Automotive News’ PACE program is recognized globally as the most prestigious innovation award for automotive suppliers.

In today’s dynamic global economic environment, we remain deeply committed to prioritizing profitability and adaptability. Although the global shift toward electrification is advancing more slowly than initially anticipated, we are confident that the long-term trajectory remains strong. Our growing roster of leading customers positions us to capitalize on this significant opportunity. By diligently managing our fixed costs and capacity planning, we aim to deliver profitable growth in a capital-efficient manner. With a focus on energy security and the continuing evolution of electrification, we are well-positioned to create lasting value as these transformative trends unfold.

Aspen’s accomplishments are built on the exceptional efforts of our team, whose dedication drives us forward every day. On behalf of our leadership, I want to sincerely thank you for the trust and support you’ve placed in us. We remain committed to building strong, ethical relationships with all our stakeholders and consistently strive to deliver results that go above and beyond your expectations.

Sincerely,

Donald R. Young

President & Chief Executive Officer

TABLE OF CONTENTS

PROXY STATEMENT FOR THE ASPEN AEROGELS, INC.

2025 ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON APRIL 30, 2025

This proxy statement, along with the accompanying notice of 2025 annual meeting of stockholders, contains information about the 2025 annual meeting of stockholders of Aspen Aerogels, Inc., including any adjournments or postponements of the annual meeting. We are holding the annual meeting at 9:30 a.m. Eastern Time on Wednesday, April 30, 2025. This year’s annual meeting will be conducted solely via live audio webcast on the Internet. You will be able to attend our annual meeting, vote and submit your questions during the annual meeting by visiting www.virtualshareholdermeeting.com/ASPN2025. You will not be able to attend the annual meeting in person.

In this proxy statement, we refer to Aspen Aerogels, Inc. as “Aspen Aerogels,” “the Company,” “we,” “our” and “us.”

This proxy statement relates to the solicitation of proxies by our Board of Directors (the “Board of Directors” or the “Board”) for use at the annual meeting.

On or about March 17, 2025, we intend to begin sending to our stockholders entitled to vote at the annual meeting the Notice of Internet Availability of Proxy Materials containing instructions on how to access our proxy statement for the 2025 annual meeting of stockholders and our 2024 annual report. Stockholders who have previously requested to receive paper copies of our proxy materials will receive paper copies of the proxy materials instead of a Notice of Internet Availability.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE

ANNUAL STOCKHOLDER MEETING TO BE HELD ON APRIL 30, 2025

This proxy statement and our 2024 annual report to stockholders are available for viewing, printing and downloading at www.proxyvote.com. In order to view, print or download these materials, please have the 16-digit control number(s) that appears on your notice or proxy card available. On this website, you can also elect to receive future distributions of our proxy statements and annual reports to stockholders by electronic delivery.

Additionally, you can find a copy of our Annual Report on Form 10-K, which includes our financial statements, for the fiscal year ended December 31, 2024 on the website of the Securities and Exchange Commission, or the SEC, atwww.sec.gov, or in the “SEC Filings” tab of the “Financials” subsection of the “Investors” section of our website at www.aerogel.com. You may also obtain a printed copy of our Annual Report on Form 10-K, including our financial statements, from us, free of charge, by sending a written request to:

Attn: Investor Relations

Exhibits will be provided upon written request and payment of an appropriate processing fee.