SCHEDULE: Klaviyo Founder Bialecki's 42.9% Stake Confirmed

Andrew Bialecki, co-founder of Klaviyo, Inc., reports beneficial ownership of 42.9% of the company's Series A common stock as of June 30, 2025.

Summary

• Andrew Bialecki, a co-founder of Klaviyo, Inc., beneficially owns 87,796,336 shares of Klaviyo's Series A common stock, representing 42.9% of the class.
• This ownership stake is reported as of June 30, 2025.
• The total beneficial ownership includes shares held directly by Mr. Bialecki (74,773,276 shares), shares held by his spouse (43,218 shares), and shares held by various trusts where Mr. Bialecki or his spouse serve as trustees (totaling 12,462,842 shares).

Sentiment

Score: 7

Explanation: The filing reports a substantial beneficial ownership by a co-founder, which is generally viewed positively as it aligns management's interests with shareholders. No negative information or risks were disclosed.

Positives

• The significant beneficial ownership of 42.9% by co-founder Andrew Bialecki indicates strong alignment of interests between management and shareholders.
• High insider ownership can signal confidence in the company's long-term prospects and strategic direction.

Future Outlook

The filing reports a beneficial ownership stake as of a future date, June 30, 2025, indicating the expected ownership structure at that time.

Industry Context

This filing is a routine disclosure of beneficial ownership by a significant insider, common for publicly traded companies, and does not directly relate to broader industry trends or competitive dynamics.

Related Party Transactions

• Beneficial ownership includes 43,218 shares held by the Reporting Person's spouse.
• Beneficial ownership includes 11,945,830 shares held by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, for which the Reporting Person serves as trustee.
• Beneficial ownership includes 517,006 shares held by the Andrew P. Bialecki Irrevocable GST Trust of 2023, for which the Reporting Person's spouse serves as a trustee.
• Beneficial ownership includes 517,006 shares held by the Elizabeth L. Bialecki Irrevocable GST Trust of 2023, for which the Reporting Person serves as a trustee.

Stakeholder Impact

• Shareholders may view the significant insider ownership as a positive signal of long-term commitment and confidence in the company's future.

Key Dates

Keywords

Klaviyo, Andrew Bialecki, Beneficial Ownership, Series A Common Stock, Insider Ownership, SEC Filing, Schedule 13G, Founder Stake