Casdin Partners Master Fund, L.P.
Director · Ten-percent owner · BLFS
As of 2026-09-16, Casdin Partners Master Fund, L.P. has 37 Form 4 transactions on record across 1 company — 16 in the trailing 12 months.
Everything this person has disclosed to the SEC on Form 4 — across every company they file for — reconstructed from the public record. A filing history, not a tip sheet.
Reconstructed holdings
- Direct $0
- Indirect $215.1M
| BLFS | indirect | 5,957,165 sh | $215.1M |
Reconstructed from this person's own Form 4 filings — the total each filing reported owning afterward, priced at the close on the as-of date shown. A filed position can lag the real one.
Direct and indirect holdings (e.g. through a trust or fund) are tagged separately, as filed.
Trades by company
Filing ledger
| Date | Company | Action | Shares @ price | Value | Ownership Δ | Owned after | Filing |
|---|---|---|---|---|---|---|---|
| 2025-12-04 | — | Purchase | 150,000 @ $1.45 | $217K | +0.2% of holding | 72,100,000 | Form 4 |
| 2025-12-03 | — | Purchase | 75,000 @ $1.44 | $108K | +0.1% of holding | 71,950,000 | Form 4 |
| 2025-12-02 | — | Purchase | 125,000 @ $1.42 | $178K | +0.2% of holding | 71,875,000 | Form 4 |
| 2025-11-25 | — | Purchase | 7,550,000 @ $1.30 | $9.8M | +11.8% of holding | 71,750,000 | Form 4 |
| 2025-11-24 | — | Purchase | 150,000 @ $1.43 | $215K | +0.2% of holding | 64,200,000 | Form 4 |
| 2025-11-20 | — | Purchase | 450,000 @ $1.30 | $586K | +0.7% of holding | 64,050,000 | Form 4 |
| 2025-11-19 | — | Purchase | 350,000 @ $1.28 | $449K | +0.6% of holding | 63,600,000 | Form 4 |
| 2025-11-18 | — | Purchase | 275,000 @ $1.23 | $339K | +0.4% of holding | 63,250,000 | Form 4 |
| 2025-11-17 | — | Purchase | 225,000 @ $1.22 | $276K | +0.4% of holding | 62,975,000 | Form 4 |
| 2025-11-14 | — | Purchase | 250,000 @ $1.24 | $310K | +0.4% of holding | 62,750,000 | Form 4 |
| 2025-11-13 | — | Purchase | 450,000 @ $1.20 | $541K | +0.7% of holding | 62,500,000 | Form 4 |
| 2025-11-12 | — | Purchase | 375,000 @ $1.19 | $446K | +0.6% of holding | 62,050,000 | Form 4 |
| 2025-11-11 | — | Purchase | 300,000 @ $1.20 | $359K | +0.5% of holding | 61,675,000 | Form 4 |
| 2025-11-10 | — | Purchase | 275,000 @ $1.17 | $322K | +0.5% of holding | 61,375,000 | Form 4 |
| 2025-11-07 | — | Purchase | 225,000 @ $1.12 | $253K | +0.4% of holding | 61,100,000 | Form 4 |
| 2025-10-15 | BLFS | Sale | 750,000 @ $28.55 | $21.4M | −11.2% of holding | 5,957,165 | Form 4 |
| 2025-09-09 | — | Purchase | 100,000 @ $1.29 | $129K | +0.2% of holding | 60,875,000 | Form 4 |
| 2025-09-04 | — | Purchase | 250,000 @ $1.28 | $319K | +0.4% of holding | 60,775,000 | Form 4 |
| 2025-09-03 | — | Purchase | 250,000 @ $1.27 | $316K | +0.4% of holding | 60,525,000 | Form 4 |
| 2025-08-26 | — | Purchase | 125,000 @ $1.26 | $158K | +0.2% of holding | 60,275,000 | Form 4 |
| 2025-08-25 | — | Purchase | 200,000 @ $1.24 | $248K | +0.3% of holding | 60,150,000 | Form 4 |
| 2025-08-22 | — | Purchase | 200,000 @ $1.26 | $253K | +0.3% of holding | 59,950,000 | Form 4 |
| 2025-08-15 | BLFS | Sale | 500,000 @ $24.40 | $12.2M | −6.9% of holding | 6,707,165 | Form 4 |
| 2025-08-15 | — | Purchase | 150,000 @ $1.22 | $183K | +0.3% of holding | 59,750,000 | Form 4 |
| 2025-08-14 | — | Purchase | 133,220 @ $1.21 | $162K | +0.2% of holding | 59,600,000 | Form 4 |
| 2025-08-13 | — | Purchase | 75,000 @ $1.31 | $98K | +0.1% of holding | 59,466,780 | Form 4 |
| 2025-08-11 | BLFS | Sale | 500,000 @ $22.60 | $11.3M | −6.5% of holding | 7,207,165 | Form 4 |
| 2025-06-10 | BLFS | Sale | 1,000,000 @ $23.80 | $23.8M | −11.5% of holding | 7,707,165 | Form 4 |
| 2025-02-28 | — | Purchase | 4,820,959 @ $1.06 | $5.1M | +8.9% of holding | 58,846,780 | Form 4 |
8 award / exercise / gift records — not counted as purchases
| Date | Company | Action | Shares | Owned after | Filing |
|---|---|---|---|---|---|
| 2025-04-07 | BLFS | Other acquisition | 27,994 | 8,735,159 | Form 4 |
| 2025-04-07 | BLFS | Other acquisition | 27,994 | 8,735,159 | Form 4 |
| 2025-04-07 | BLFS | Other acquisition | 27,994 | 8,735,159 | Form 4 |
| 2025-04-07 | BLFS | Other acquisition | 27,994 | 8,735,159 | Form 4 |
| 2025-04-07 | BLFS | Other acquisition | 27,994 | 8,735,159 | Form 4 |
| 2025-02-28 | — | Other acquisition | 545,000 | 0 | Form 4 |
| 2025-02-28 | — | Other acquisition | 545,000 | 59,391,780 | Form 4 |
| 2025-02-28 | — | Award / grant | 58,215 | 2,806,470 | Form 4 |
Source: SEC Form 4 filings. Each row links to its original filing.
Research tool, not investment advice — historical frequencies, not recommendations. A product of Marovel Technologies LLC. Full terms.