Description of the Registrants Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934, as amended

As of December 31, 2021, Semrush Holdings, Inc. (“we,” “our” or “us”) had one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”): our Class A common stock, $0.00001 per share. The following descriptions are summaries of the material terms of our amended and restated certificate of incorporation and amended and restated bylaws. Because it is only a summary, it does not contain all the information that may be important to you. For a complete description of the matters set forth in this section titled “Description of Capital Stock,” you should refer to our amended and restated certificate of incorporation, amended and restated bylaws, and our investor’ rights agreement, which are included as exhibits to the Annual Report on Form 10-K of which this Exhibit 4.3 is a part, and to the applicable provisions of Delaware law.

Our authorized capital stock consists of 1,000,000,000 shares of Class A common stock, $0.00001 par value per share, 160,000,000 shares of Class B common stock, $0.00001 par value per share, and 100,000,000 shares of undesignated preferred stock, $0.00001 par value per share.

Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of our common stock are entitled to receive dividends out of funds legally available if our board of directors, in its discretion, determines to issue dividends and then only at the times and in the amounts that our board of directors may determine.

Holders of our Class A common stock are entitled to one vote for each share, and holders of our Class B common stock are entitled to 10 votes per share, on all matters submitted to a vote of stockholders. The holders of our Class A common stock and Class B common stock generally vote together as a single class on all matters submitted to a vote of our stockholders, unless otherwise required by Delaware law or our amended and restated certificate of incorporation. Delaware law could require either holders of our Class A common stock or Class B common stock to vote separately as a single class in the following circumstances:

•if we were to seek to amend our amended and restated certificate of incorporation to increase or decrease the par value of a class of our capital stock, then that class would be required to vote separately to approve the proposed amendment; and

•if we were to seek to amend our amended and restated certificate of incorporation in a manner that alters or changes the powers, preferences, or special rights of a class of our capital stock in a manner that affected its holders adversely, then that class would be required to vote separately to approve the proposed amendment.

Our amended and restated certificate of incorporation does not provide for cumulative voting for the election of directors. Our amended and restated certificate of incorporation and amended and restated bylaws established a classified board of directors that is divided into three classes with staggered three-year terms. Only the directors in one class are subject to election by a plurality of the votes cast at each

annual meeting of our stockholders, with the directors in the other classes continuing for the remainder of their respective three-year terms.

Our common stock is not entitled to preemptive rights, and is not subject to conversion, redemption, or sinking fund provisions.

If we become subject to a liquidation, dissolution or winding-up, the assets legally available for distribution to our stockholders would be distributable ratably among the holders of our common stock and any participating preferred stock outstanding at that time, subject to prior satisfaction of all outstanding debt and liabilities and the preferential rights of and the payment of liquidation preferences, if any, on any outstanding shares of preferred stock.

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. Shares of Class B common stock automatically convert into shares of Class A common stock upon sale or transfer, except certain transfers described in our amended and restated certificate of incorporation, including transfers for estate planning or tax purposes to: (i) family members, (ii) Qualifying Trustees of trusts for the benefit of the stockholder and/or their family members (except for remote contingent interests), and (iii) partnerships, corporations, and other entities owned by the stockholder or their family members or trusts described above. In addition, each outstanding share of Class B common stock held by a stockholder who is a natural person, or held by the permitted entities and permitted transferees of such natural person (as described in our amended and restated certificate of incorporation), convert automatically into one share of Class A common stock upon the death of such natural person.

Each share of Class B common stock will convert automatically into one share of Class A common stock upon (i) the date specified by affirmative vote of the holders of two-thirds of the then outstanding shares of Class B common stock, (ii) the date on which the outstanding shares of Class B common stock represent less than 10% of the aggregate number of shares of the then outstanding Class A common stock and Class B common stock, or (iii) March 24, 2028.

Once converted into a single class of common stock, the Class A and Class B common stock may not be reissued.

All of the outstanding shares of our Class A common stock and Class B common stock are fully paid and non-assessable.

Our board of directors is authorized, subject to limitations prescribed by Delaware law, to issue preferred stock in one or more series, to establish from time to time the number of shares to be included in each series and to fix the designation, powers, preferences, and rights of the shares of each series and any of its qualifications, limitations or restrictions, in each case without further vote or action by our stockholders. Our board of directors can also increase or decrease the number of shares of any series of preferred stock, but not below the number of shares of that series then outstanding, without any further vote or action by our stockholders. Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders

of our common stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring, or preventing a change in control of our company and might adversely affect the market price of our Class A common stock and the voting and other rights of the holders of our Class A common stock and Class B common stock. We have no current plan to issue any shares of preferred stock.

Certain holders of our Class B common stock are entitled to rights with respect to the registration of their shares under the Securities Act. These registration rights are contained in our Investors’ Rights Agreement, or the IRA, dated as of December 19, 2019. We, along with certain holders of our Class B common stock (including shares of our common stock issued or issuable upon conversion of our preferred stock and any other convertible securities), including our founders, Oleg Shchegolev and Dmitry Melnikov, are parties to the IRA. The registration rights set forth in the IRA will expire upon the earliest to occur of a deemed liquidation event or, with respect to any particular stockholder, when such stockholder is able to sell all of its shares pursuant to Rule 144 of the Securities Act during any three-month period. In an underwritten offering, the underwriters have the right, subject to specified conditions, to limit the number of shares such holders may include.

Certain holders of our Class B common stock are entitled to certain demand registration rights. We are obligated to effect only one such registration. If we determine that it would be materially detrimental to our stockholders to effect such a demand registration, we have the right to defer such registration, not more than once in any 12-month period, for a period of up to 120 days. Additionally, we will not be required to effect a demand registration during the period beginning 60 days prior to our good faith estimate of the date of the filing of, and ending up to 180 days following the effectiveness of, a registration statement relating to the public offering of our common stock.

If we propose to register the offer and sale of our common stock under the Securities Act, in connection with the public offering of such common stock certain holders of our Class B common stock are entitled to certain “piggyback” registration rights allowing the holders to include their shares in such registration, subject to certain marketing and other limitations. As a result, whenever we propose to file a registration statement under the Securities Act, other than with respect to (1) a registration related to a company stock plan, (2) a registration pursuant to Rule 145 of the Securities Act, (3) a registration on any form that does not include substantially the same information as would be required to be included in a registration statement covering the public offering of our common stock or (4) a registration in which the only common stock being registered is common stock issuable upon the conversion of debt securities that are also being registered, the holders of these shares are entitled to notice of the registration and have the right, subject to certain limitations, to include their shares in the registration.

Certain holders of our Class B common stock may make a written request that we register the offer and sale of their shares on a registration statement on Form S-3 if we are eligible to file a registration statement on Form S-3 so long as the request covers at least that number of shares with an anticipated offering price, net of underwriting discounts and commissions, of at least $5 million. These stockholders may make an unlimited number of requests for registration on Form S-3; however, we will not be required to effect a registration on Form S-3 if we have effected two such registrations within the 12-month period preceding the date of the request. If we determine that it would be materially detrimental to our stockholders to effect such a registration, we have the right to defer such registration, not more than once

in any 12-month period, for a period of up to 90 days. Additionally, we will not be required to effect a registration on Form S-3 during the period beginning 30 days prior to our good faith estimate of the date of the filing of, and ending up to 90 days following the effectiveness of, a registration statement relating to the public offering of our common stock.

The provisions of Delaware law, our amended and restated certificate of incorporation, and our amended and restated bylaws, which are summarized below, may have the effect of delaying, deferring, or discouraging another person from acquiring control of our company. They are also designed, in part, to encourage persons seeking to acquire control of us to negotiate first with our board of directors. We believe that the benefits of increased protection of our potential ability to negotiate with an unfriendly or unsolicited acquirer outweigh the disadvantages of discouraging a proposal to acquire us because negotiation of these proposals could result in an improvement of their terms.

We are governed by the provisions of Section 203 of the Delaware General Corporation Law. In general, Section 203 prohibits a public Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless the business combination is approved in a prescribed manner. A “business combination” includes mergers, asset sales or other transactions resulting in a financial benefit to the stockholder. An “interested stockholder” is a person who, together with affiliates and associates, owns, or within three years did own, 15% or more of the corporation’s outstanding voting stock. These provisions may have the effect of delaying, deferring, or preventing a change in our control.

Our amended and restated certificate of incorporation and our amended and restated bylaws include a number of provisions that could deter hostile takeovers or delay or prevent changes in control of our board of directors or management team, including the following:

•Authorized but Unissued Shares. The authorized but unissued shares of our common stock and our preferred stock are available for future issuance without stockholder approval, subject to any limitations imposed by the listing standards of the NYSE. These additional shares may be used for a variety of corporate finance transactions, acquisitions, and employee benefit plans. The existences of authorized but unissued and unreserved common stock and preferred stock could make more difficult or discourage an attempt to obtain control of us by means of a proxy contest, tender offer, merger or otherwise.

•Dual Class Stock. As described above in the subsection titled “—Class A Common Stock and Class B Common Stock—Voting Rights,” our amended and restated certificate of incorporation provides for a dual class common stock structure, which provides our founders, current investors, executives, and employees with significant influence 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 of its assets.

•Board of Directors Vacancies. Our amended and restated certificate of incorporation and amended and restated bylaws authorize only our board of directors to fill vacant directorships, including newly created seats. In addition, the number of directors constituting our board of

directors is permitted to be set only by a resolution adopted by a majority vote of our entire board of directors. These provisions prevent a stockholder from increasing the size of our board of directors and then gaining control of our board of directors by filling the resulting vacancies with its own nominees. These provisions make it more difficult to change the composition of our board of directors and promote continuity of management.

•Classified Board. Our amended and restated certificate of incorporation and amended and restated bylaws provide that our board of directors is classified into three classes of directors. A third-party may be discouraged from making a tender offer or otherwise attempting to obtain control of us as it is more difficult and time consuming for stockholders to replace a majority of the directors on a classified board of directors. See the section titled “Management—Board of Directors.”

•Stockholder Action; Special Meeting of Stockholders. Our amended and restated certificate of incorporation provides that our stockholders may not take action by written consent but may only take action at annual or special meetings of our stockholders. As a result, a holder controlling a majority of our capital stock is not able to amend our amended and restated bylaws or remove directors without holding a meeting of our stockholders called in accordance with our amended and restated bylaws. Our amended and restated bylaws further provide that special meetings of our stockholders may be called only by a majority of our board of directors, thus prohibiting a stockholder from calling a special meeting. These provisions might delay the ability of our stockholders to force consideration of a proposal or for stockholders controlling a majority of our capital stock to take any action, including the removal of directors.

•Advance Notice Requirements for Stockholder Proposals and Director Nominations. Our amended and restated bylaws provide advance notice procedures for stockholders seeking to bring business before our annual meeting of stockholders or to nominate candidates for election as directors at our annual meeting of stockholders. Our amended and restated bylaws also specify certain requirements regarding the form and content of a stockholder’s notice. These provisions might preclude our stockholders from bringing matters before our annual meeting of stockholders or from making nominations for directors at our annual meeting of stockholders if the proper procedures are not followed. We expect that these provisions may also discourage or deter a potential acquirer from conducting a solicitation of proxies to elect the acquirer’s own slate of directors or otherwise attempting to obtain control of our company.

•No Cumulative Voting. The Delaware General Corporation Law provides that stockholders are not entitled to cumulate votes in the election of directors unless a corporation’s certificate of incorporation provides otherwise. Our amended and restated certificate of incorporation does not provide for cumulative voting.

•Directors Removed Only for Cause. Our amended and restated certificate of incorporation provides that stockholders may remove directors only for cause.

•Amendment of Charter Provisions. Any amendment of the above provisions in our amended and restated certificate of incorporation requires approval by holders of at least two-thirds of the voting power of our then outstanding capital stock.

•Issuance of Undesignated Preferred Stock. Our board of directors has the authority, without further action by the stockholders, to issue up to 100,000,000 shares of undesignated preferred stock with rights and preferences, including voting rights, designated from time to time by our board of directors. The existence of authorized but unissued shares of preferred stock enables our board of directors to render more difficult or to discourage an attempt to obtain control of us by means of a merger, tender offer, proxy contest, or other means.

•Exclusive Forum. Our amended and restated bylaws provide that, unless we consent in writing to an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any state law claim for (1) any derivative action or proceeding brought on our behalf, (2) any action asserting a claim of breach of or based on a fiduciary duty owed by any of our current or former directors, officers, or employees to us or our stockholders, (3) any action asserting a claim arising pursuant to any provision of the Delaware General Corporation Law, our amended and restated certificate of incorporation or our amended and restated bylaws (including the interpretation, validity or enforceability thereof) or (4) any action asserting a claim that is governed by the internal affairs doctrine, in each case subject to the Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein, or the Delaware Forum Provision. The Delaware Forum Provision will not apply to any causes of action arising under the Securities Act or the Exchange Act. Our amended and restated bylaws further provide that, unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States shall be the sole and exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act. In addition, our amended and restated bylaws provide that any person or entity purchasing or otherwise acquiring any interest in shares of our common stock is deemed to have notice of and consented to the foregoing provisions; provided, however, that stockholders cannot and will not be deemed to have waived our compliance with the federal securities laws and the rules and regulations thereunder. This exclusive forum provision will not apply to suits brought to enforce any liability or duty created by the Exchange Act. The enforceability of similar choice of forum provisions in other companies’ certificates of incorporation and bylaws has been challenged in legal proceedings, and it is possible that a court could find these types of provisions to be inapplicable or unenforceable.

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 and registrar’s address is 250 Royall Street, Canton, Massachusetts 02021, and its telephone number is ###-###-####.

Our Class A common stock is listed on the NYSE under the symbol “SEMR.”