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

Klaviyo CEO Andrew Bialecki converted and sold 100,000 shares of Series A Common Stock for approximately $3.3 million under a pre-arranged trading plan.

Summary

• Andrew Bialecki, Klaviyo's Chief Executive Officer, Director, and 10% Owner, reported transactions on December 22, 2025.
• Bialecki converted 100,000 shares of Series B Common Stock into 100,000 shares of Series A Common Stock.
• Immediately following the conversion, Bialecki sold 93,066 shares of Series A Common Stock at a weighted average price of $33.05 per share.
• An additional 6,934 shares of Series A Common Stock were sold at a weighted average price of $31.94 per share.
• The total proceeds from these sales amount to approximately $3,296,470.26.
• All reported transactions were executed pursuant to a Rule 10b5-1 trading plan adopted by Bialecki on May 20, 2025.
• Following these transactions, Bialecki directly holds 0 shares of Series A Common Stock.
• Bialecki continues to directly hold 69,568,889 shares of Series B Common Stock and indirectly holds additional Series B shares through various trusts and his spouse.

Sentiment

Score: 5

Explanation: The transactions represent a pre-planned sale by the CEO, which is a neutral event. While it is insider selling, the existence of a 10b5-1 plan mitigates concerns about opportunistic timing.

Positives

• The transactions were conducted under a pre-arranged Rule 10b5-1 trading plan, indicating the sales were not based on immediate, non-public information.

Negatives

• The CEO's sale of a significant number of shares, even if planned, could be perceived negatively by some investors.

Future Outlook

N/A

Management Comments

• The transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025.

Industry Context

N/A

Related Party Transactions

• Andrew Bialecki disclaims Section 16 beneficial ownership of shares held by The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023 (7,517,410 Series B shares), The Elizabeth L. Bialecki Irrevocable GST Trust of 2023 (517,006 Series B shares), and The Andrew P. Bialecki Irrevocable GST Trust of 2023 (517,006 Series B shares), except to the extent of his pecuniary interest therein.
• Andrew Bialecki also indirectly holds 43,218 Series B Common Stock shares through his spouse.

Stakeholder Impact

• Shareholders may observe the CEO's planned share sales, which could influence market sentiment, though the 10b5-1 plan suggests a non-event-driven disposition.

Key Dates

Recommendation

The CEO's sale of shares was conducted under a pre-arranged 10b5-1 trading plan, which suggests the transaction was not based on new, material non-public information. While insider selling can sometimes be viewed negatively, the planned nature of this sale makes it a more neutral event. Investors should monitor future filings and company performance rather than reacting solely to this planned disposition.

Keywords

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