Prime Medicine, Inc. insider trading
Every open-market purchase and sale by Prime Medicine, Inc.'s officers, directors and largest shareholders since November 4, 2021, and what the share price did next.
Does following Prime Medicine, Inc.’s insiders pay?
From February 20, 2024 to August 5, 2025, 6 insiders reported 10 open-market purchases and 0 sales not made under a pre-set plan in Prime Medicine, Inc. Twelve months after each purchase was reported, the shares were −87.5% against the S&P 500 on average (median −87.5%), over 1 purchase with a full year of prices; 0% beat the index. That rests on fewer than 20 purchases, too few to read much into. Buying each purchase the day after it was reported, an equal amount each, held 12 months or until that insider reported a sale, would have turned $10,000 on February 21, 2024 into $3,737 by November 2, 2026, −30.7% a year. It held shares 37% of the time; the S&P 500 on those same days, with Treasury bills otherwise, made $13,079 (+10.5% a year), and held throughout $15,712 (+18.3%).
| Insider | Role | Purchases | 12 months after their purchases | Beat the S&P 500 | Sales | 12 months after their sales | Latest report |
|---|---|---|---|---|---|---|---|
| Liu David R. | 10% owner | 4 | — | — | 0 | — | July 1, 2025 |
| Nelsen Robert | Director | 2 | −87.5% (1) | 0% | 0 | — | August 1, 2025 |
| Alphabet Inc. | 10% owner | 1 | — | — | 0 | — | August 5, 2025 |
| Brudnick Richard | Chief Business Officer | 1 | — | — | 0 | — | May 22, 2025 |
| Lee Ann L. | Chief Technical Officer | 1 | — | — | 0 | — | May 22, 2025 |
| Reine Allan | Chief Executive Officer | 1 | — | — | 0 | — | May 22, 2025 |
When several insiders traded Prime Medicine, Inc.
Months when 2 or more insiders became net buyers, or 3 or more net sellers, of Prime Medicine, Inc. in reports dated in the 91 days before the month end, and how the stock did against the S&P 500 from that month end. After the 1 buying crowd with six months of prices, it averaged −60.6% against the index. One company's history is too short to judge by; the test across every company is the better guide.
| Month | Crowd | 3 months on, vs S&P 500 | 6 months | 12 months |
|---|---|---|---|---|
| February 29, 2024 | 2 buying | −27.9% | −60.6% | −89.4% |