- Quarter end
- 31 Dec 2025
- the date the book describes
- Filed
- 19 Feb 2026
- latest of these filings; the earliest 5 Feb 2026
- Managers listing it
- 24
- at least, of 95 tracked, among listed positions
- Comparable managers
- 92
- filed both Q3 2025 and Q4 2025; 7 listed it in both
- Shares listed
- 19,911,884
- combined, among listed positions
- Reported value
- $340m
- combined, at the quarter end
Among the 92 comparable managers: 17 buyers (opened or added shares) and 6 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was +1,724,448.
Managers listing BLCO in Q4 2025
24 of 24 holders
Largest increases and reductions, by shares
Increases
- Davidson Kempner Capital Management LPexisting position · 1,939,711 shares now+959,237
- D. E. Shaw & Co.existing position · 2,846,625 shares now+239,625
- Citadel Advisors LLCexisting position · 911,329 shares now+209,109
- Arrowstreet Capital LPexisting position · 1,211,740 shares now+150,047
- Oaktree Capital Management LPexisting position · 3,382,739 shares now+137,300
Reductions
- Fidelity (FMR LLC)existing position · 1,445,333 shares now-114,793
- Squarepoint Ops LLCexisting position · 31,767 shares now-109,654
- Woodline Partners LPexisting position · 771,876 shares now-89,177
- GAMCO Investors Incexisting position · 17,000 shares now-68,000
- Tudor Investment Corpexisting position · 91,269 shares now-58,001
New positions and exits
New (6)
Exited (0)
No exit shown by a manager’s own filing.
Ownership over time
Tracked managers listing it, at least.
| Quarter | Holders | Reported value | Buyers | Sellers |
|---|---|---|---|---|
| Q2 2022 | 3 | $63m | n.a. | n.a. |
| Q3 2022 | 4 | $100m | n.a. | n.a. |
| Q4 2022 | 2 | $63m | n.a. | n.a. |
| Q1 2023 | 2 | $90m | n.a. | n.a. |
| Q2 2023 | 3 | $87m | n.a. | n.a. |
| Q3 2023 | 4 | $69m | n.a. | n.a. |
| Q4 2023 | 4 | $66m | 1 | 1 |
| Q1 2024 | 4 | $73m | 3 | 0 |
| Q2 2024 | 5 | $74m | 2 | 1 |
| Q3 2024 | 5 | $97m | 2 | 2 |
| Q4 2024 | 5 | $82m | 1 | 3 |
| Q1 2025 | 3 | $59m | 2 | 0 |
| Q2 2025 | 4 | $101m | 3 | 0 |
| Q3 2025 | 7 | $158m | 4 | 0 |
| Q4 2025 | 7 | $198m | 17 | 6 |
| Q1 2026 | 5 | $178m | 11 | 12 |
| Q2 2026 | 6 | $203m | 16 | 7 |
Compare with…
Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.
BLCO and LLY →BLCO and JNJ →BLCO and VRTX →Choose a stock to compare with BLCO →
How much of the picture this is
A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.
Which funds own BLCO, latest filings →Back to the 13F Explorer →