Form 4: Klaviyo CEO Sells $7M in Stock Under 10b5-1 Plan

Klaviyo CEO Andrew Bialecki sold 238,648 shares of Series A Common Stock for approximately $7.07 million through pre-arranged trading plans.

Summary

• Andrew Bialecki, CEO, Director, and 10% Owner of Klaviyo, Inc. (KVYO), executed sales of Series A Common Stock.
• These transactions were conducted under a Rule 10b5-1 trading plan adopted on May 20, 2025.
• On December 16, 2025, Bialecki converted 138,648 shares of Series B Common Stock into Series A Common Stock and subsequently sold all 138,648 Series A shares at a weighted average price of $29.04 per share, totaling approximately $4,026,000.
• On December 17, 2025, Bialecki converted an additional 100,000 shares of Series B Common Stock into Series A Common Stock and sold all 100,000 Series A shares at a weighted average price of $30.40 per share, totaling approximately $3,040,000.
• Following these direct transactions, Bialecki's direct beneficial ownership of Series A Common Stock is 0 shares, while his direct beneficial ownership of Series B Common Stock is 69,668,889 shares.
• Indirect holdings of Series B Common Stock include 7,517,410 shares held by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, 517,006 shares by the Elizabeth L. Bialecki Irrevocable GST Trust of 2023, 517,006 shares by the Andrew P. Bialecki Irrevocable GST Trust of 2023, and 43,218 shares by his spouse.

Sentiment

Score: 5

Explanation: The sentiment is neutral. While insider selling can sometimes be viewed negatively, these transactions were conducted under a pre-arranged 10b5-1 plan, which mitigates concerns about opportunistic selling. It represents a planned diversification or liquidity event for the CEO rather than a signal of company distress.

Positives

• Transactions were executed under a pre-arranged Rule 10b5-1 trading plan, indicating a structured and pre-planned approach to stock sales rather than an immediate reaction to market conditions.
• The sales occurred at prices ranging from $28.58 to $30.71, indicating a favorable market price for the shares at the time of sale.

Negatives

• Significant insider selling by the CEO, Director, and 10% owner could be perceived negatively by some investors, potentially signaling a desire to diversify personal holdings.

Future Outlook

This Form 4 filing does not contain any forward-looking statements or guidance regarding the company's future performance or strategic direction.

Management Comments

• The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Industry Context

This filing reports an insider transaction and does not provide broader industry context. The sale of shares by a CEO, even under a 10b5-1 plan, is a common occurrence for executives managing personal wealth and diversification, and does not inherently reflect on Klaviyo's competitive position or industry trends.

Comparison to Industry Standards

• Not applicable. This filing details personal stock transactions of an executive, not company performance metrics that can be benchmarked against industry standards or competitors.

Related Party Transactions

• Shares are indirectly held by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, of which the Reporting Person serves as trustee.
• Shares are indirectly held by the Elizabeth L. Bialecki Irrevocable GST Trust of 2023, of which the Reporting Person serves as a trustee.
• Shares are indirectly held by the Andrew P. Bialecki Irrevocable GST Trust of 2023, of which the Reporting Person's spouse serves as a trustee.
• Shares are indirectly held by the Reporting Person's spouse.

Stakeholder Impact

• Shareholders: The sale of shares by a key executive could lead to short-term negative sentiment or questions about management's long-term commitment, though the 10b5-1 plan mitigates this. The remaining significant holdings (over 69 million Series B shares directly, plus trust holdings) indicate continued substantial alignment with shareholder interests.
• Employees: No direct impact on employees is indicated by this filing.
• Customers/Suppliers/Creditors: No direct impact on these stakeholders is indicated by this filing.

Next Steps

• The Reporting Person undertakes to provide full information regarding the number of shares sold at each separate price within the reported ranges upon request.

Key Dates

Recommendation

The filing details pre-planned insider sales by the CEO under a Rule 10b5-1 plan. While significant in value, these sales are generally for personal financial planning and diversification, not a direct reflection of the company's immediate operational performance or future prospects. The CEO retains a very substantial direct and indirect stake in the company. Therefore, this event alone does not warrant a change in investment thesis, suggesting a 'hold' position for existing investors, while new investors should evaluate the company's fundamentals independently of this planned insider transaction.

Keywords

Klaviyo, KVYO, Andrew Bialecki, Insider Trading, Form 4, Stock Sale, 10b5-1 Plan, CEO, Director, Series A Common Stock, Series B Common Stock