Form 4: Adaptive Bio CSO Sells Shares Under 10b5-1 Plan

Adaptive Biotechnologies' Chief Scientific Officer, Harlan S. Robins, reported the sale of 42,788 shares of common stock through a pre-arranged 10b5-1 trading plan.

Summary

• Harlan S. Robins, Chief Scientific Officer of Adaptive Biotechnologies Corp (ADPT), reported the sale of common stock.
• On February 2, 2026, 34,668 shares were sold at a weighted average price of $18.6 per share, with prices ranging from $18.26 to $18.88.
• On February 3, 2026, an additional 8,120 shares were sold at a weighted average price of $19 per share, with prices ranging from $18.56 to $19.38.
• These transactions were executed under a Rule 10b5-1 trading plan adopted on August 11, 2025.
• Following these sales, Robins beneficially owns 1,179,524 shares of common stock.

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 reduces the immediate negative signaling typically associated with open market insider selling.

Positives

• The sales were conducted under a pre-arranged Rule 10b5-1 trading plan, indicating a planned liquidity event rather than a reaction to new negative information.

Negatives

• An insider, the Chief Scientific Officer, sold a significant number of shares (42,788 shares in total).

Industry Context

StockSavvy.ai notes that insider sales, even when pre-planned under a 10b5-1 plan, are routinely monitored by investors for potential signals regarding management's confidence in the company's future prospects. While a 10b5-1 plan mitigates the immediate negative interpretation, the volume and frequency of such sales across multiple insiders can sometimes indicate a broader trend.

Related Party Transactions

• Harlan S. Robins, Chief Scientific Officer, sold 42,788 shares of Adaptive Biotechnologies Corp common stock in two transactions on February 2 and February 3, 2026, under a Rule 10b5-1 trading plan.

Stakeholder Impact

• Shareholders may view the insider sale as a slight negative, though the 10b5-1 plan mitigates concerns about immediate adverse company developments.
• The company's management team maintains a significant equity stake, indicating continued alignment with shareholder interests despite the partial liquidation.

Key Dates

Recommendation

The insider sales, while notable, were executed under a pre-arranged 10b5-1 plan, which suggests a planned liquidity event rather than a reaction to new, undisclosed negative information. This mitigates the typical negative signal of insider selling. Without additional company-specific news or broader market context, a 'hold' recommendation is appropriate as this filing alone does not provide a strong catalyst for a 'buy' or 'sell' decision.

Keywords

Adaptive Biotechnologies, ADPT, Form 4, Insider Trading, Harlan S. Robins, Chief Scientific Officer, Stock Sale, 10b5-1 Plan, Equity Transaction