ACV Auctions Inc.

Our Section 16 officers (as defined in Rule 16a-1 under the Exchange Act) may from time to time enter into plans for the purchase or sale of ACV stock that are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act.

During the quarter ended June 30, 2026, the following Section 16 officers adopted, modified, or terminated “Rule 10b5-1 trading arrangements” (as defined in Item 408 under Regulation S-K of the Exchange Act):

•On June 15, 2026, Andrew Peer, ACV's Chief Accounting Officer, adopted a trading plan. Mr. Peer's trading plan provides for the sale of up to 8,000 shares plus a number of shares to be determined based on the number of certain unsold shares under Mr. Peer's prior trading plan and a number of shares to be determined based on net vesting of RSUs. The first trade will not occur until September 14, 2026 at the earliest. Mr. Peer's trading plan is scheduled to terminate on May 28, 2027.

The Rule 10b5-1 trading arrangements described above were terminated, modified, adopted, and pre-cleared in accordance with ACV’s Insider Trading Policy and actual sale transactions made pursuant to any such trading arrangements have been or will be disclosed publicly in past or future Section 16 filings with the SEC. Other than disclosed above, no other officer adopted, modified orterminated a Rule 10b5-1 trading arrangement or “non-Rule 10b5-1 trading arrangement” (as defined in Item 408 of Regulation S-K) during the three months ended June 30, 2026.

On May 4, 2026, The Compensation Committee (the "Committee") of the Board of Directors (the "Board") of ACV Auctions (the "Company") approved, and the Company entered into, severance agreements (each, a "Severance Agreement") with each the Company's Chief Executive Officer and the Company's other executive officers (each, an "Executive" and collectively, the "Executives").

The Severance Agreements replace the existing Severance and Change of Control Plan and Participation Agreements previously entered into between the Company and each Executive. Each Severance Agreement provides that, in the event the Executive's employment is terminated by the Company without Cause or the Chief Executive Officer resigns for Good Reason (each as defined in the Severance Agreement), not in connection with a Change in Control (as defined in the Severance Agreement), the Executive will be entitled to receive the following severance benefits, subject to the Executive's timely execution and non-revocation of a general release of claims in favor of the Company.

•A lump sum cash severance payment equal to (A) 1.5 times (in the case of the Chief Executive Officer) and 1.0 times (in the case of each other Executive) the sum of the Executive's annual base salary and (B) a pro-rated annual bonus for the fiscal year of termination if Executive was employed by Company for more than 182 days in the year termination occurred based on the actual achievement of the applicable performance criteria as measured at the end of such year payable in a lump sum

•Participation in the Company's group health and dental plans on the same terms as active employees (or, if such continuation is not permitted, a monthly cash payment equal to the applicable COBRA premium) for a period of 18 months (in the case of the Chief Executive Officer) or 12 months (in the case of each other Executive) following the date of termination

•Accelerated vesting of each outstanding time-based equity award held by the Executive as of the date of termination that would have vested during the 18-month period (in the case of the Chief Executive Officer) or 12-month period (in the case of each other Executive) immediately following the date of termination

Each Severance Agreement further provides that, in the event the Executive's employment is terminated by the Company without Cause or the Executive resigns for Good Reason during the period beginning three months prior to and ending 12 months following a Change in Control (the "Change in Control Protection Period"), the Executive will be entitled to receive the following enhanced severance benefits, in lieu of the severance benefits described above:

•a lump sum cash severance payment equal to (A) 2.0 times (in the case of the Chief Executive Officer) or 1.5 times (in the case of each other Executive) the sum of the Executive's annual base salary and (B) 1.5 times (in the case of the Chief Executive Officer) or 1.0 times (in the case of each other Executive) the Executive's target annual bonus, in each case as in effect immediately prior to the date of termination (or, if higher, as in effect immediately prior to the Change in Control);

•participation in the Company's group health and dental plans on the same terms as active employees (or, if such continuation is not permitted, a monthly cash payment equal to the applicable COBRA premium) for a period of

24 months (in the case of the Chief Executive Officer) or 18 months (in the case of each other Executive) following the date of termination

•full accelerated vesting of all outstanding time-based equity awards held by the Executive as of the date of termination;

•full accelerated vesting of all outstanding performance-based equity awards held by the Executive as of the date of termination, with performance deemed achieved at the greater of target or actual performance through the most recently completed measurement period.

The severance benefits under each Severance Agreement are subject to the Executive's continued compliance with all applicable restrictive covenants, including confidentiality, non-competition, non-solicitation of employees, and non-solicitation of customers,

The foregoing description of the Severance Agreements does not purport to be complete and is qualified in its entirety by reference to the full text of the form of Executive Severance Agreement (CEO-Tier 1) and the form of Executive Severance Agreement (Executive-Tier 2), copies of which are referenced as Exhibits 10.1 and 10.2 herein.