Form 4 Filing for Klaviyo, Inc.

This filing details derivative transactions by Shopify Strategic Holdings 3 LLC and Shopify Inc. on April 28, 2026. Shopify Strategic Holdings 3 LLC disposed of 344,381 warrants to purchase Series B Common Stock, with 25% vesting on July 28, 2022, and the remainder vesting quarterly through July 28, 2027. In connection with the IPO, 25% of the total warrant shares vested immediately prior. The post-transaction shares for these warrants are 1,721,912. Additionally, Shopify Strategic Holdings 3 LLC acquired 344,381 shares of Series B Common Stock at $0.01 per share, with a post-transaction total of 16,973,108 shares. Each Series B share is convertible into one Series A share, with no expiration date, and automatic conversion upon certain events. Shopify Inc. is the indirect beneficial owner of these securities.