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

Klaviyo's Co-Chief Executive Officer, Andrew Bialecki, executed pre-planned sales of Series A Common Stock totaling 206,827 shares on March 10, 2026, following a conversion from Series B shares.

Summary

• Andrew Bialecki, Co-Chief Executive Officer, Director, and 10% Owner of Klaviyo, Inc. (KVYO), reported transactions in the company's securities.
• On March 10, 2026, Bialecki converted 206,827 shares of Series B Common Stock into an equal number of Series A Common Stock.
• Immediately following the conversion, Bialecki sold 206,127 shares of Series A Common Stock at a weighted average price of $19.96 per share, with prices ranging from $19.375 to $20.37.
• An additional 700 shares of Series A Common Stock were sold at a weighted average price of $19.34 per share, with prices ranging from $19.28 to $19.37.
• These transactions were conducted pursuant to a Rule 10b5-1 trading plan adopted on May 20, 2025.
• Following these transactions, Bialecki directly holds 68,344,118 shares of Series B Common Stock (convertible to Series A) and indirectly holds additional Series B shares through various trusts and his spouse.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral event. While it's an insider sale, the execution under a pre-planned 10b5-1 plan mitigates concerns about immediate negative sentiment or a lack of confidence from the Co-CEO.

Positives

• The transactions were executed under a pre-arranged Rule 10b5-1 trading plan, indicating a planned liquidity event rather than a reaction to recent negative company news.

Negatives

• A significant insider sale by a Co-CEO, Director, and 10% owner could be perceived negatively by some investors, even if pre-planned.

Industry Context

StockSavvy.ai notes that insider sales, even when pre-planned under a 10b5-1 plan, are common for executives seeking to diversify their personal holdings or manage tax liabilities. Such sales are generally viewed differently than unplanned, opportunistic sales, which can signal a lack of confidence in the company's near-term prospects. For a high-growth tech company like Klaviyo, executive liquidity events are a natural part of maturation.

Related Party Transactions

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

Stakeholder Impact

• Shareholders may interpret the insider sale differently; some may see it as a normal diversification, while others might view it as a negative signal, potentially leading to short-term price volatility.

Key Dates

Recommendation

The insider sale by Co-CEO Andrew Bialecki, while substantial, was conducted under a pre-arranged 10b5-1 trading plan, which typically indicates a planned liquidity event rather than a reaction to new, negative company developments. This mitigates the immediate negative signal often associated with insider selling. Investors should monitor future company performance and broader market conditions for Klaviyo, as this transaction alone does not fundamentally alter the investment thesis, but it also doesn't provide a strong positive catalyst.

Keywords

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