Citadel Advisors (Ken Griffin) — BIIB Trade History
Quarter-by-quarter changes in the BIOGEN INC position · CUSIP 09062X103
Currently held · 2 YearsFirst seen: 2015 Q4
| Quarter | Filed | Activity | Shares | Δ Shares | Δ % | Value | % Port. |
|---|---|---|---|---|---|---|---|
| 2026 Q2 | 2026-09-02 | Add | 418,356 | 280,263 | +203.0% | $90.4M | 0.01% |
| 2026 Q1 | 2026-05-15 | Add | 138,093 | 97,669 | +241.6% | $25.3M | 0.00% |
| 2025 Q4 | 2026-02-17 | Reduce | 40,424 | -332,304 | -89.2% | $7.1M | 0.00% |
| 2025 Q3 | 2025-11-14 | Reduce | 372,728 | -235,862 | -38.8% | $52.2M | 0.01% |
| 2025 Q2 | 2025-08-14 | Add | 608,590 | 66,826 | +12.3% | $76.4M | 0.01% |
| 2025 Q1 | 2025-05-15 | Add | 541,764 | 388,104 | +252.6% | $74.1M | 0.01% |
| 2024 Q4 | 2025-02-14 | Reduce | 153,660 | -218,706 | -58.7% | $23.5M | 0.00% |
| 2024 Q3 | 2024-11-14 | New | 372,366 | 372,366 | — | $72.2M | 0.01% |
| 2024 Q2 | 2024-08-14 | Sold out | — | -149,298 | -100.0% | — | — |
| 2024 Q1 | 2024-05-15 | Add | 149,298 | 144,037 | +2737.8% | $32.2M | 0.01% |
| 2023 Q4 | 2024-02-14 | Reduce | 5,261 | -72,875 | -93.3% | $1.4M | — |
| 2023 Q3 | 2023-11-14 | New | 78,136 | 78,136 | — | $20.1M | 0.00% |
| 2023 Q2 | 2023-08-14 | Sold out | — | -245,084 | -100.0% | — | — |
| 2023 Q1 | 2023-05-15 | Reduce | 245,084 | -2,728 | -1.1% | $68.1M | 0.01% |
| 2022 Q4 | 2023-02-14 | Reduce | 247,812 | -1,566 | -0.6% | $68.6M | 0.02% |
| 2022 Q3 | 2022-11-14 | Add | 249,378 | 40,935 | +19.6% | $66.6M | 0.01% |
| 2022 Q2 | 2022-08-15 | Add | 208,443 | 130,048 | +165.9% | $42.5M | 0.01% |
| 2022 Q1 | 2022-05-16 | New | 78,395 | 78,395 | — | $16.5M | 0.00% |
| 2021 Q3 | 2022-03-11 | Sold out | — | -89,241 | -100.0% | — | — |
| 2021 Q4 | 2022-02-14 | Reduce | 89,241 | -467,648 | -84.0% | $21.4M | 0.00% |
| 2021 Q2 | 2021-08-16 | Add | 556,889 | 333,326 | +149.1% | $192.8M | 0.04% |
| 2021 Q1 | 2021-05-21 | Reduce | 223,563 | -126,331 | -36.1% | $62.5M | 0.01% |
| 2020 Q4 | 2021-02-16 | Add | 349,894 | 326,285 | +1382.0% | $85.7M | 0.02% |
| 2020 Q3 | 2020-11-16 | Reduce | 23,609 | -114,656 | -82.9% | $6.7M | 0.00% |
| 2020 Q2 | 2020-08-14 | Reduce | 138,265 | -74,638 | -35.1% | $37.0M | 0.01% |
| 2020 Q1 | 2020-05-15 | Reduce | 212,903 | -16,694 | -7.3% | $67.4M | 0.03% |
| 2019 Q4 | 2020-02-14 | New | 229,597 | 229,597 | — | $68.1M | 0.03% |
| 2019 Q2 | 2020-02-14 | — | — | — | — | — | — |
| 2018 Q4 | 2019-11-14 | Sold out | — | -144,182 | -100.0% | — | — |
| 2019 Q3 | 2019-11-14 | New | 144,182 | 144,182 | — | $33.6M | 0.02% |
| 2018 Q2 | 2019-08-14 | — | — | — | — | — | — |
| 2018 Q3 | 2019-05-15 | Sold out | — | -149,416 | -100.0% | — | — |
| 2019 Q1 | 2019-05-15 | New | 149,416 | 149,416 | — | $35.3M | 0.02% |
| 2018 Q1 | 2019-02-14 | Sold out | — | -160,964 | -100.0% | — | — |
| 2017 Q4 | 2018-02-09 | Reduce | 160,964 | -502,732 | -75.7% | $51.3M | 0.03% |
| 2017 Q3 | 2017-11-09 | Reduce | 663,696 | -402,870 | -37.8% | $207.8M | 0.16% |
| 2017 Q2 | 2017-08-11 | Add | 1,066,566 | 275,284 | +34.8% | $289.4M | 0.24% |
| 2017 Q1 | 2017-05-12 | Add | 791,282 | 209,550 | +36.0% | $216.4M | 0.20% |
| 2016 Q4 | 2017-02-10 | Reduce | 581,732 | -65,639 | -10.1% | $165.0M | 0.17% |
| 2015 Q4 | 2017-01-31 | New | 647,371 | 647,371 | — | $198.3M | 0.22% |
Share counts are split-adjusted. Time held counts consecutive quarters ending with the latest filing; more than ten years shows as ">10 Years".
13F data shows quarter-end positions, is delayed by up to 45 days and covers only long positions in US-listed securities; short positions, most derivatives and non-US assets are not reported.