Form 4: Duolingo CTO Sells Shares Under Pre-Planned Trading Plan

Duolingo Co-Founder and CTO Severin Hacker sold 9,900 Class A Common Stock shares on September 5, 2025, following the exercise of options and conversion of Class B shares, all under a Rule 10b5-1 plan.

Summary

• Severin Hacker, Duolingo's Co-Founder, Chief Technology Officer, Director, and 10% Owner, engaged in multiple transactions on September 5, 2025.
• Exercised stock options to acquire 10,000 Class B Common Stock shares at an exercise price of $38.08 per share. These options were fully vested.
• Converted a total of 20,000 Class B Common Stock shares into Class A Common Stock.
• Acquired 10,000 Class A Common Stock shares at a price of $38.08, likely resulting from one of the conversions.
• Sold a total of 9,900 Class A Common Stock shares in multiple transactions at weighted average prices ranging from $264.7464 to $271.5717.
• All sales were conducted pursuant to a pre-arranged Rule 10b5-1 trading plan adopted on September 11, 2024.
• Following these transactions, Hacker's direct beneficial ownership of Class A Common Stock is 72 shares, and direct beneficial ownership of Class B Common Stock is 86,075 shares.
• Hacker also indirectly holds 2,886,917 Class B Common Stock shares through the SBH Trust dated March 10, 2020, of which he is Trustee.

Sentiment

Score: 4

Explanation: The sentiment is neutral to slightly negative. While the sales were pre-planned under a 10b5-1 plan, significant insider selling by a co-founder and CTO can still be viewed with caution by investors, despite the substantial gains realized from option exercise. The pre-planned nature mitigates the negative impact but does not eliminate it entirely.

Positives

• The exercise of stock options at a significantly lower price ($38.08) compared to the market sale prices (ranging from $264.18 to $271.63) indicates a substantial personal gain on the exercised options.
• The sales were conducted under a Rule 10b5-1 trading plan, which suggests the transactions were pre-scheduled and not based on immediate, non-public information, mitigating concerns about opportunistic insider selling.

Negatives

• Significant insider selling of 9,900 Class A Common Stock shares by a key executive and co-founder, which could be perceived negatively by investors, even if pre-planned.

Future Outlook

No forward-looking statements or guidance are provided in this filing.

Industry Context

This filing details an insider transaction specific to Duolingo and its co-founder. It does not provide information directly related to broader industry trends or competitive landscape, beyond the general market conditions that influence the company's stock price.

Related Party Transactions

• Severin Hacker indirectly holds 2,886,917 Class B Common Stock shares through the SBH Trust dated March 10, 2020, of which he is the Trustee. This represents a standard disclosure for beneficial ownership through a related entity.

Stakeholder Impact

• Shareholders: May interpret the insider selling as a signal, potentially leading to short-term price volatility. The pre-planned nature (Rule 10b5-1) generally reduces the negative inference compared to unplanned sales, but it still represents a reduction in insider ownership.

Key Dates

Recommendation

The transactions involve significant insider selling by a key executive, which typically warrants caution. However, the sales were executed under a pre-arranged Rule 10b5-1 plan, mitigating the immediate negative signal often associated with insider sales. The executive still retains substantial indirect holdings. Investors should monitor future insider activity and company performance rather than reacting solely to this pre-planned disposition.

Keywords

Duolingo, DUOL, Severin Hacker, insider trading, Form 4, stock options, Class A Common Stock, Class B Common Stock, Rule 10b5-1 plan, CTO, co-founder, share sale