Insider Selling Hot‑Spot at Adaptive Biotechnologies
The recent Form 4 filed by Chief Scientific Officer Harlan Robins on February 2, 2026, shows a sizable sell‑off of 34,668 shares at an average price of $18.60. Two days later, Robins completed an additional 8,120‑share sale at $19.00. Combined, the officer has liquidated roughly 42,788 shares, reducing his holdings from 1,232,312 to 1,179,524 shares. The trades were executed under a Rule 10b5‑1 trading plan adopted on August 11, 2025, indicating that the sales were pre‑planned rather than opportunistic.
What Does This Mean for Investors?
On the surface, large insider sales can signal a lack of confidence in the company’s trajectory. However, the context matters. Robins’ average sale price ($18.85) is well above the recent close of $18.50 and slightly below the 52‑week high of $20.76, suggesting that he is not dumping at a distressed level. Moreover, the trades occurred while the market was in a broader downtrend—weekly change at –6.49%—so the pricing is not indicative of a sudden collapse in fundamentals. The company’s negative P/E of –34.14 and modest price‑to‑book of 13.71 point to a valuation that is still far from earnings generation, but the steady quarterly reviews and lack of new product announcements suggest that management remains cautious, not panic‑driven.
For the long‑term investor, the key takeaway is that insider selling under a 10b5‑1 plan can be a routine liquidity event rather than a red flag. The fact that the officer’s holdings remain in the 1.18‑million‑share range—over 40% of the public float—indicates ongoing commitment. The current market cap of $2.82 billion and a market price that sits roughly in the mid‑range of its 52‑week band support a valuation that is neither overbought nor oversold.
Robins: A Profile of Consistent Selling
Across the past year, Robins has executed four major sell trades:
- Jan 6, 2026 – 10,000 shares at $16.44
- Dec 4, 2025 – 10,000 shares at $16.61
- Dec 3, 2025 – 27,212 shares at $18.61
- Feb 2, 2026 – 34,668 shares at $18.60
- Feb 3, 2026 – 8,120 shares at $19.00
His transactions are spread over a 10‑month period and generally align with a steady, disciplined selling schedule. The average sale price over this period is $18.55, roughly 1% above the February close. Robins has not taken any large purchases in the same window, suggesting that his strategy is not one of portfolio rebalancing but of gradual liquidity management.
The officer’s trading pattern is consistent with a Rule 10b5‑1 plan: the trades are executed in increments, at prices that reflect normal market conditions, and the overall volume is a small fraction of his total holdings each time. This disciplined approach is common among senior executives who wish to avoid the “insider trading” stigma while still providing for personal cash needs.
Company-Wide Insider Activity in Context
The recent company‑wide filing also shows CEO and Chairman Chad Robins selling 124,998 shares on February 2, 2026. This is the single largest trade in the current period and, together with the CSO’s sales, represents a combined liquidation of over 160,000 shares. Yet, the CEO’s holding after the sale is still 2.46 million shares—more than 90% of the public float—underscoring a continued confidence in Adaptive’s long‑term prospects.
Bottom Line
Insider sales under a Rule 10b5‑1 plan are not inherently ominous. For Adaptive Biotechnologies, the recent sell‑off by Harlan Robins appears to be a routine liquidity event within a broader, stable ownership structure. Investors should view the transactions as part of a normal executive cash‑flow strategy rather than a signal of impending weakness. The company’s valuation remains comfortably below its 52‑week high, and the management team continues to hold sizeable positions—an indicator that, despite short‑term selling, they maintain a long‑term stake in the firm’s future.
| Date | Owner | Transaction Type | Shares | Price per Share | Security |
|---|---|---|---|---|---|
| 2026-02-02 | ROBINS HARLAN S (Chief Scientific Officer) | Sell | 34,668.00 | 18.60 | Common Stock |
| 2026-02-03 | ROBINS HARLAN S (Chief Scientific Officer) | Sell | 8,120.00 | 19.00 | Common Stock |
| 2026-02-02 | ROBINS CHAD M (CEO and Chairman) | Sell | 124,998.00 | 18.44 | Common Stock |




