Klaviyo Announces Filing of Registration Statement for Proposed Initial Public Offering

Boston, August 25, 2023  Klaviyo, Inc., the company that powers smarter digital
relationships, today announced that it has publicly filed a registration statement on Form S-1 with
the U.S. Securities and Exchange Commission (the “SEC”) relating to a proposed initial public
offering of its Series A common stock. The number of shares to be offered and the price range
for the proposed offering have not yet been determined. The offering is subject to market
conditions, 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 stock
on 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 the
proposed offering. Barclays, Mizuho, and William Blair, are acting as joint book runners, Piper
Sandler and Truist Securities are additionally acting as book runners, and Baird, Canaccord
Genuity, 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 preliminary
prospectus, 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 by
telephone at 1-800-831-9146.

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

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

About Klaviyo

Klaviyo (CLAY-vee-oh) powers smarter digital relationships, making it easy for businesses to
capture, store, analyze, and predictively use their own data to drive measurable, high-value
outcomes. Klaviyo’s modern and intuitive SaaS platform enables business users of any skill level
to 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.