Casdin Partners Master Fund, L.P.
CIK 1534265 · last filed 2025-12-04
Casdin Partners Master Fund, L.P. is a corporate insider who has filed 7 SEC Form 4 insider transactions across 5 companies since 2021. The most recent filing shows the insider bought $4.0M of LAB on Dec 4, 2025. Across all open-market trades the lifetime net is −$38.6M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $449.2M across reported positions.
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
$449.18M
5
7
-$38.56M
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| LAB | Director | 74,851,062 | $0.89 | $66.45M | $15.02M | 2 | 2025-12-04 |
| BLFS | 10%+ Owner | 14,664,330 | $26.10 | $382.74M | -$85.64M | 2 | 2025-10-17 |
| 2seventy bio, Inc. (TSVT) Delisted | Director | 2,016,600 | $5.00 | $10.08M | $816.0K | 1 | 2024-03-28 |
| Verve Therapeutics, Inc. (VERV) Delisted | 10%+ Owner | 1,007,311 | $11.13 | $11.21M | $20.90M | 1 | 2021-06-22 |
| Decibel Therapeutics, Inc. (DBTX) Delisted | 10%+ Owner | 546,421 | $4.91 | $2.68M | $10.35M | 1 | 2021-02-19 |
Recent Filings
7 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2025-12-04 | LAB | Buy (P) | +2,800,000 | $4.02M | EDGAR |
| 2025-11-20 | LAB | Buy (P) | +8,600,000 | $11.00M | EDGAR |
| 2025-10-17 | BLFS | Sell (S) | −3,000,000 | -$85.64M | EDGAR |
| 2024-05-02 | BLFS | Other (J) | — | $0 | EDGAR |
| 2024-03-28 | 2seventy bio, Inc. (TSVT) Delisted | Buy (P) | +160,000 | $816.0K | EDGAR |
| 2021-06-22 | Verve Therapeutics, Inc. (VERV) Delisted | Mixed | +2,417,596 | $20.90M | EDGAR |
| 2021-02-19 | Decibel Therapeutics, Inc. (DBTX) Delisted | Mixed | +1,121,421 | $10.35M | EDGAR |