Form 4: Klaviyo CEO Sells Shares Under 10b5-1 Plan

Klaviyo CEO Andrew Bialecki sold 163,331 shares of Series A Common Stock for approximately $24.37 per share, executed under a pre-arranged 10b5-1 trading plan.

Summary

• Andrew Bialecki, Chief Executive Officer, Director, and 10% Owner of Klaviyo, Inc., executed a transaction on October 14, 2025.
• The transaction involved the conversion of 163,331 shares of Series B Common Stock into Series A Common Stock.
• Concurrently, 163,331 shares of Series A Common Stock were sold.
• The sales were conducted at a weighted average price of $24.37 per share, with individual transaction prices ranging from $23.67 to $24.655.
• These transactions were carried out pursuant to a Rule 10b5-1 trading plan adopted on May 20, 2025.
• Following these transactions, Andrew Bialecki directly holds 0 shares of Series A Common Stock and 74,133,406 shares of Series B Common Stock.
• Significant indirect holdings of Series B Common Stock through various trusts and by spouse remain, totaling 8,077,640 shares.

Sentiment

Score: 5

Explanation: Neutral. The filing reports a routine insider transaction (sale) executed under a pre-arranged 10b5-1 plan, which is generally not indicative of new positive or negative company-specific news. It represents a planned liquidity event for the insider.

Positives

• NA

Negatives

• NA

Risks

• NA

Future Outlook

NA

Industry Context

NA

Related Party Transactions

• Shares held indirectly by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, the Elizabeth L. Bialecki Irrevocable GST Trust of 2023, the Andrew P. Bialecki Irrevocable GST Trust of 2023, and by spouse are disclosed. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any.

Stakeholder Impact

• Shareholders may observe a slight increase in the public float of Series A Common Stock due to the sale.
• The sale by a key executive could be interpreted by some investors as a signal, though the execution under a 10b5-1 plan mitigates immediate negative interpretations.

Key Dates

Recommendation

The sale by CEO Andrew Bialecki was executed under a pre-arranged Rule 10b5-1 trading plan, which typically indicates a planned liquidity event rather than a reaction to new material non-public information. While insider sales can sometimes be viewed negatively, the existence of a 10b5-1 plan mitigates this concern. Given the significant remaining indirect holdings of Series B Common Stock, this transaction alone does not provide a strong signal for a 'buy' or 'sell' recommendation, suggesting a 'hold' position based solely on this filing.

Keywords

Klaviyo, KVYO, Andrew Bialecki, Insider Sale, Form 4, 10b5-1 Plan, CEO, Stock Transaction, Equity Sale