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

Klaviyo CEO Andrew Bialecki sold 140,464 shares of Series A Common Stock for a weighted average price of $29.74 per share, executed under a pre-arranged 10b5-1 trading plan.

Summary

• Andrew Bialecki, CEO, Director, and 10% Owner of Klaviyo, Inc., reported transactions on November 11, 2025.
• He converted 140,464 shares of Series B Common Stock into an equal number of Series A Common Stock.
• Immediately following the conversion, he sold all 140,464 shares of Series A Common Stock.
• The shares were sold at a weighted average price of $29.74, with individual transactions ranging from $29.21 to $30.01 per share.
• These transactions were conducted under a Rule 10b5-1 trading plan established on May 20, 2025.
• Following these transactions, Andrew Bialecki directly holds 0 shares of Series A Common Stock but retains significant direct and indirect beneficial ownership of Series B Common Stock.

Sentiment

Score: 5

Explanation: The sentiment is neutral. While an insider sale can sometimes be viewed negatively, the execution under a pre-arranged 10b5-1 plan mitigates concerns about opportunistic selling based on undisclosed material information. It's a routine transaction for many executives for diversification or liquidity purposes.

Positives

• The sale was executed under a pre-arranged Rule 10b5-1 trading plan, indicating a planned and not reactive transaction.

Negatives

• A significant insider sale by the CEO could be perceived negatively by some investors, even if pre-planned.

Risks

• Potential negative market perception due to an insider sale, which could put downward pressure on the stock price.

Future Outlook

NA

Industry Context

This Form 4 filing reports an insider transaction and does not provide information directly related to broader industry trends or competitive landscape.

Related Party Transactions

• The filing details indirect beneficial ownership through various trusts (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, which are considered related party holdings.

Stakeholder Impact

• Shareholders may react to the insider sale, potentially leading to short-term stock price volatility, though the 10b5-1 plan context may temper negative sentiment.
• Employees, customers, suppliers, and creditors are unlikely to be directly impacted by this specific insider transaction.

Key Dates

Recommendation

The insider sale by CEO Andrew Bialecki, while significant in volume, was conducted under a pre-established 10b5-1 trading plan. This suggests a planned liquidity event rather than a reaction to new, undisclosed negative information about Klaviyo. Given the pre-planned nature and the CEO's continued substantial beneficial ownership of Series B Common Stock, this transaction alone does not warrant a change in investment thesis. Investors should 'hold' and monitor future company performance and broader market conditions rather than reacting solely to this routine insider transaction.

Keywords

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