Exhibit 4.2

DESCRIPTION OF THE REGISTRANT’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934

As of December 31, 2021, ACV Auctions Inc. had one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended, or the Exchange Act: our Class A common stock, $0.001 par value per share. References herein to the terms “we,” “our” and “us” refer to ACV Auctions Inc. and its subsidiaries.

The following description of our capital stock is a summary and does not purport to be complete. It is subject to, and qualified in its entirety by reference to, the applicable provisions of our amended and restated certificate of incorporation, our amended and restated bylaws and our investor rights agreement, most recently amended in September 2020, each of which are filed as exhibits to our Annual Report on Form 10-K, of which this Exhibit 4.2 is a part, and are incorporated by reference herein. We encourage you to read our amended and restated certificate of incorporation, our amended and restated bylaws, our investor rights agreement and the applicable provisions of the Delaware General Corporation Law for more information.

General

Our amended and restated certificate of incorporation provides for two classes of common stock: Class A common stock and Class B common stock. In addition, our amended and restated certificate of incorporation authorizes shares of undesignated preferred stock, the rights, preferences and privileges of which may be designated from time to time by our board of directors and filed in accordance with Delaware law.

Our authorized capital stock consists of 2,180,000,000 shares, all with a par value of $0.001 per share, of which 2,000,000,000 shares are designated Class A common stock, 160,000,000 shares are designated Class B common stock, and 20,000,000 shares are designated preferred stock.

Our board of directors is authorized, without stockholder approval except as required by the listing standards of Nasdaq, to issue additional shares of our capital stock.

Class A Common Stock and Class B Common Stock

Voting Rights

The Class A common stock is entitled to one vote per share on any matter that is submitted to a vote of our stockholders. Holders of our Class B common stock are entitled to ten votes per share on any matter submitted to our stockholders. Holders of shares of Class B common stock and Class A common stock will vote together as a single class on all matters (including the election of directors) submitted to a vote of stockholders, unless otherwise required by Delaware law.

Under Delaware law, holders of our Class A common stock or Class B common stock would be entitled to vote as a separate class if a proposed amendment to our amended and restated certificate of incorporation would increase or decrease the aggregate number of authorized shares of such class, increase or decrease the par value of the shares of such class, or alter or change the powers, preferences or special rights of the shares of such class so as to affect them adversely. As a result, in these limited instances, the holders of a majority of the Class A common stock could defeat any amendment to our amended and restated certificate of incorporation. For example, if a proposed amendment to our amended and restated certificate of incorporation provided for the Class A common stock to rank junior to the Class B common stock with respect to (1) any dividend or distribution, (2) the distribution of proceeds were we to be acquired or (3) any other right, Delaware law would require the vote of the Class A common stock as a separate class. In this instance, the holders of a majority of Class A common stock could defeat that amendment to our amended and restated certificate of incorporation.

Our amended and restated certificate of incorporation does not provide for cumulative voting for the election of directors.

Economic Rights

Except as otherwise expressly provided in our amended and restated certificate of incorporation or required by applicable law, all shares of Class A common stock and Class B common stock have the same rights, privileges and powers and rank equally, share ratably and be identical in all respects for all matters, including those described below.

Dividends and Distributions

Subject to preferences that may apply to any shares of convertible preferred stock outstanding at the time, the holders of Class A common stock and Class B common stock are entitled to share equally, identically and ratably, on a per share basis, with respect to any dividend or distribution of cash or property paid or distributed by the company, unless different treatment of the shares of the affected class is approved by the affirmative vote of the holders of a majority of the outstanding shares of such affected class, voting separately as a class.

Liquidation Rights

On our liquidation, dissolution or winding-up, the holders of Class A common stock and Class B common stock will be entitled to share equally, identically and ratably in all assets remaining after the payment of any liabilities, liquidation preferences and accrued or declared but unpaid dividends, if any, with respect to any outstanding convertible preferred stock, unless a different treatment is approved by the affirmative vote of the holders of a majority of the outstanding shares of such affected class, voting separately as a class.

Change of Control Transactions

The holders of Class A common stock and Class B common stock will be treated equally and identically with respect to shares of Class A common stock or Class B common stock owned by them, unless different treatment of the shares of each class is approved by the affirmative vote of the holders of a majority of the outstanding shares of the class treated differently, voting separately as a class, on (1) the completion of the sale, transfer or other disposition of all or substantially all of our assets, (2) the consummation of a merger, reorganization, consolidation or share transfer which results in our voting securities outstanding immediately before the transaction (or the voting securities issued with respect to our voting securities outstanding immediately before the transaction) representing less than a majority of the combined voting power of the voting securities of the company or the surviving or acquiring entity or (3) the completion of the transfer (whether by merger, consolidation or otherwise), in one transaction or a series of related transactions, to a person or group of affiliated persons of securities of the company if, after closing, the transferee person or group would hold 50% or more of the outstanding voting power of the company (or the surviving or acquiring entity). However, consideration to be paid or received by a holder of common stock in connection with any such assets sale, merger, reorganization, consolidation or share transfer under any employment, consulting, severance or other arrangement will be disregarded for the purposes of determining whether holders of common stock are treated equally and identically.

Subdivisions and Combinations.

If we subdivide or combine in any manner outstanding shares of Class A common stock or Class B common stock, the outstanding shares of the other classes will be subdivided or combined in the same manner.

No Preemptive or Similar Rights

Our Class A common stock and Class B common stock are not entitled to preemptive rights, and are not subject to conversion, redemption or sinking fund provisions, except for the conversion provisions with respect to the Class B common stock described below.

Conversion

Each share of Class B common stock is convertible at any time at the option of the holder into one share of Class A common stock. On any transfer of shares of Class B common stock, whether or not for value, each such transferred share will automatically convert into one share of Class A common stock, except for certain transfers described in our amended and restated certificate of incorporation, including transfers for tax and estate planning purposes, so long as the transferring holder continues to hold sole voting and dispositive power with respect to the shares transferred.

Any holder’s shares of Class B common stock will convert automatically into shares of Class A common stock, on a one-to-one basis, upon the following: (1) the sale or transfer of such share of Class B common stock, subject to certain exceptions; (2) the death of the Class B common stockholder; and (3) the final conversion date, defined as the earlier of (a) the last trading day of the fiscal quarter immediately following the tenth anniversary of our initial public offering; and (b) the last trading day of the fiscal quarter during which the then-outstanding shares of Class B common stock first represent less than 5.0% of the aggregate number of then-outstanding shares of Class A common stock and Class B common stock; subject to certain exceptions.

Once transferred and converted into Class A common stock, the Class B common stock may not be reissued.

Registration Rights

We are party to an investors’ rights agreement that provides that certain holders of our capital stock, including certain holders of at least 5% of our capital stock and entities affiliated with certain of our directors, have certain registration rights, as set forth

below. The registration of shares of our common stock by the exercise of registration rights described below would enable the holders to sell these shares without restriction under the Securities Act of 1933, as amended, or the Securities Act, when the applicable registration statement is declared effective. We will pay the registration expenses, other than underwriting discounts and commissions, of the shares registered by the demand, piggyback and Form S-3 registrations described below.

Generally, in an underwritten offering, the managing underwriter, if any, has the right, subject to specified conditions, to limit the number of shares such holders may include. The demand, piggyback and Form S-3 registration rights under our investors rights agreement will expire upon the earliest to occur of: (1) the closing of a “Deemed Liquidation Event”, as defined in our amended and restated certificate of incorporation in effect immediately prior to the completion of our initial public offering; or (2) with respect to any particular stockholder, such time as such stockholder can sell all of its shares under Rule 144 of the Securities Act or another similar exemption during any three-month period.

Anti-Takeover Provisions

Certificate of Incorporation and Bylaws

Because our stockholders do not have cumulative voting rights, stockholders holding a majority of the voting power of our shares of common stock will be able to elect all of our directors. Our amended and restated certificate of incorporation and amended and restated bylaws provide for stockholder actions at a duly called meeting of stockholders. A special meeting of stockholders may be called by a majority of our board of directors, the chair of our board of directors, our chief executive officer or our lead independent director. Our amended and restated bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of our stockholders, including proposed nominations of persons for election to our board of directors.

Our amended and restated certificate of incorporation further provides for a dual-class common stock structure, which provides our current investors, officers and employees with control over all matters requiring stockholder approval, including the election of directors and significant corporate transactions, such as a merger or other sale of our company or its assets.

In accordance with our amended and restated certificate of incorporation, our board of directors is divided into three classes with staggered three-year terms.

The foregoing provisions will make it more difficult for another party to obtain control of us by replacing our board of directors. Since our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to change our control.

These provisions, including the dual-class structure of our common stock, are intended to preserve our existing control structure, facilitate our continued product innovation and the risk-taking that it requires, permit us to continue to prioritize our long-term goals rather than short-term results, enhance the likelihood of continued stability in the composition of our board of directors and its policies and to discourage certain types of transactions that may involve an actual or threatened acquisition of us. These provisions are also designed to reduce our vulnerability to an unsolicited acquisition proposal and to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and may have the effect of deterring hostile takeovers or delaying changes in our control or management. As a consequence, these provisions may also inhibit fluctuations in the market price of our stock that could result from actual or rumored takeover attempts.

Section 203 of the Delaware General Corporation Law

We are subject to Section 203 of the Delaware General Corporation Law, which prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, subject to certain exceptions.

Choice of Forum

Our amended and restated certificate of incorporation provides that the Court of Chancery of the State of Delaware (or, if and only if the Court of Chancery of the State of Delaware lacks subject matter jurisdiction, any state court located within the State of Delaware or, if and only if all such state courts lack subject matter jurisdiction, the federal district court for the District of Delaware) is the sole and exclusive forum for the following claims or causes of action under Delaware statutory or common law: (1) any derivative claim or cause of action brought on our behalf; (2) any claim or cause of action asserting a claim of breach of a fiduciary duty owed by any of our current or former directors, officers, or other employees to us or our stockholders; (3) any claim or cause of action against us or any of our current or former directors, officers or other employees arising out of or pursuant to any provision of the Delaware General Corporation Law, our amended and restated certificate of incorporation or our amended and restated bylaws; (4) any claim or cause of action arising under or seeking to interpret, apply, enforce or determine the validity of our amended and restated certificate of

incorporation or our amended and restated bylaws (including any right, obligation, or remedy thereunder); and (5) any claim or cause of action as to which the Delaware General Corporation Law confers jurisdiction on the Court of Chancery of the State of Delaware; and (6) any claim or cause of action against us or any of our current or former directors, officers, or other employees that is governed by the internal-affairs doctrine, in all cases to the fullest extent permitted by law and subject to the court having personal jurisdiction over the indispensable parties named as defendants. This choice of forum provision would not apply to suits brought to enforce a duty or liability created by the Securities Act, the Exchange Act or any other claim for which the federal courts have exclusive jurisdiction, or the Securities Act.

Our amended and restated certificate of incorporation further provides that, unless we consent in writing to the selection of an alternative forum, to the fullest extent permitted by law, the federal district courts of the United States will be the exclusive forum for resolving any complaint asserting a cause or causes of action arising under the Securities Act, including all causes of action asserted against any defendant to such complaint. For the avoidance of doubt, this provision is intended to benefit and may be enforced by us, our officers and directors, the underwriters to any offering giving rise to such complaint, and any other professional entity whose profession gives authority to a statement made by that person or entity and who has prepared or certified any part of the documents underlying the offering.

While the Delaware courts have determined that such choice of forum provisions are facially valid, there is no assurance that a court in another jurisdiction would enforce the choice of forum provision contained in the amended and restated certificate of incorporation. If a court were to find such provision to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could harm our business, results of operations and financial condition. Additionally, our amended and restated certificate of incorporation provides that any person or entity holding, owning or otherwise acquiring any interest in any of our securities shall be deemed to have notice of and consented to these provisions. Investors also cannot waive compliance with the federal securities laws and the rules and regulations thereunder.

Exchange Listing

Our Class A common stock is listed on The Nasdaq Global Select Market under the symbol “ACVA.”

Transfer Agent and Registrar

The transfer agent and registrar for our Class A common stock and Class B common stock is Computershare Trust Company, N.A. The transfer agent’s address is 250 Royall Street, Canton, Massachusetts 02021.