Klaviyo Announces Filing of Registration for Proposed IPO

Boston, August 25, 2023– Klaviyo, Inc., the company that powers smarter digitalrelationships, today announced that it has publicly filed a registration statement on Form S-1 withthe U.S. Securities and Exchange Commission (the “SEC”) relating to a proposed initial publicoffering of its Series A common stock. The number of shares to be offered and the price rangefor the proposed offering have not yet been determined. The offering is subject to marketconditions, and there can be no assurance as to whether or when the offering may be completed,or as to the actual size or terms of the offering. Klaviyo intends to list its Series A common stockon the New York Stock Exchange (“NYSE”) under the ticker symbol “KVYO.”

Goldman Sachs & Co. LLC, Morgan Stanley, and Citigroup are acting as lead book runners for theproposed offering. Barclays, Mizuho, and William Blair, are acting as joint book runners, PiperSandler and Truist Securities are additionally acting as book runners, and Baird, CanaccordGenuity, Needham & Company, and TD Cowen are acting as co-managers.

The proposed offering will be made only by means of a prospectus. Copies of the preliminaryprospectus, when available, may be obtained from: Goldman Sachs & Co. LLC, Attention:Prospectus Department, 200 West Street, New York, New York 10282, by telephone at (866) 471-2526, or by email at prospectus-ny@ny.email.gs.com; Morgan Stanley & Co. LLC, Attention:Prospectus Department, 180 Varick Street, 2nd Floor, New York, New York 10014; and Citigroup,c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717 or bytelephone at 1-800-831-9146.

A registration statement relating to these securities has been filed with the SEC but has not yetbecome effective. These securities may not be sold, nor may offers to buy be accepted, prior tothe time the registration statement becomes effective.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy thesesecurities, nor shall there be any sale of these securities in any state or jurisdiction in which suchoffer, solicitation or sale would be unlawful prior to registration or qualification under thesecurities laws of any such state or jurisdiction.

About Klaviyo

Klaviyo (CLAY-vee-oh) powers smarter digital relationships, making it easy for businesses tocapture, store, analyze, and predictively use their own data to drive measurable, high-valueoutcomes. Klaviyo’s modern and intuitive SaaS platform enables business users of any skill levelto harness their first-party data from more than 300 integrations to send the right message at the right time across email, SMS, and push notifications. Innovative businesses like Dermalogica, Living Proof, Citizen Watch, and more than 130,000 other paying users leverage Klaviyo to acquire, engage, and retain customers—and grow on their own terms.

Klaviyo-IR

# Klaviyo Announces Filing of Registration Statement for Proposed Initial Public Offering **Boston, August 25, 2023–** Klaviyo, Inc., the company that powers smarter digitalrelationships, today announced that it has publicly filed a registration statement on Form S-1 withthe U.S. Securities and Exchange Commission (the “SEC”) relating to a proposed initial publicoffering of its Series A common stock. The number of shares to be offered and the price rangefor the proposed offering have not yet been determined. The offering is subject to marketconditions, and there can be no assurance as to whether or when the offering may be completed,or as to the actual size or terms of the offering. Klaviyo intends to list its Series A common stockon the New York Stock Exchange (“NYSE”) under the ticker symbol “KVYO.” Goldman Sachs & Co. LLC, Morgan Stanley, and Citigroup are acting as lead book runners for theproposed offering. Barclays, Mizuho, and William Blair, are acting as joint book runners, PiperSandler and Truist Securities are additionally acting as book runners, and Baird, CanaccordGenuity, Needham & Company, and TD Cowen are acting as co-managers. The proposed offering will be made only by means of a prospectus. Copies of the preliminaryprospectus, when available, may be obtained from: Goldman Sachs & Co. LLC, Attention:Prospectus Department, 200 West Street, New York, New York 10282, by telephone at (866) 471-2526, or by email at prospectus-ny@ny.email.gs.com; Morgan Stanley & Co. LLC, Attention:Prospectus Department, 180 Varick Street, 2nd Floor, New York, New York 10014; and Citigroup,c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717 or bytelephone at 1-800-831-9146. A registration statement relating to these securities has been filed with the SEC but has not yetbecome effective. These securities may not be sold, nor may offers to buy be accepted, prior tothe time the registration statement becomes effective. This press release shall not constitute an offer to sell or the solicitation of an offer to buy thesesecurities, nor shall there be any sale of these securities in any state or jurisdiction in which suchoffer, solicitation or sale would be unlawful prior to registration or qualification under thesecurities laws of any such state or jurisdiction. ## About Klaviyo Klaviyo (CLAY-vee-oh) powers smarter digital relationships, making it easy for businesses tocapture, store, analyze, and predictively use their own data to drive measurable, high-valueoutcomes. Klaviyo’s modern and intuitive SaaS platform enables business users of any skill levelto harness their first-party data from more than 300 integrations to send the right message at the right time across email, SMS, and push notifications. Innovative businesses like Dermalogica, Living Proof, Citizen Watch, and more than 130,000 other paying users leverage Klaviyo to acquire, engage, and retain customers—and grow on their own terms. Klaviyo-IR