Form 13-F position report

ANNEXON INC

Reported by Bain Capital Life Sciences Investors LLC

ANNX CUSIP 03589W102 Manager CIK 0001703031

Reported 4,437,731 shares, down 774,943 (14.9%) from the prior quarter.

Reported value -12.3%; share count -14.9% vs. the prior quarter.

Reduced
% of reported 13F value 1.51% This manager · Q2 2026
Shares 4,437,731 Quarter-end amount reported
Reported value $25,339,444 Fair value at quarter end
Consecutive quarters held 24 Through Q2 2026

Reported position value by quarter

Reported position value by quarter

Each bar is a Form 13-F quarter-end snapshot. It does not show trades made within the quarter.

Reported position value by quarter
Date Holding Value
2021-09-30 60327000
2021-12-31 37246000
2022-03-31 8850000
2022-06-30 12221000
2022-09-30 22260000
2022-12-31 25264000
2023-03-31 18813000
2023-06-30 20070780
2023-09-30 13456545
2023-12-31 36600204
2024-03-31 62402432
2024-06-30 41401119
2024-09-30 50022508
2024-12-31 26927724
2025-03-31 10130703
2025-06-30 12597766
2025-09-30 16009660
2025-12-31 26350326
2026-03-31 28878214
2026-06-30 25339444

Quarterly position history

How this manager's reported quarter-end position changed over time.

20 quarters
Quarterly reported position history for ANNEXON INC held by Bain Capital Life Sciences Investors LLC.
Quarter Activity Shares Change % of reported 13F Reported value Filed Source filing
Q2 2026 Reduced 4,437,731 -774,943 (-14.9%) 1.51% $25,339,444 2026-08-14
Q1 2026 Reduced 5,212,674 -36,395 (-0.7%) 2.6% $28,878,214 2026-05-15
Q4 2025 Unchanged 5,249,069 0 (0.0%) 2.02% $26,350,326 2026-02-17
Q3 2025 Unchanged 5,249,069 0 (0.0%) 1.06% $16,009,660 2025-11-14
Q2 2025 Unchanged 5,249,069 0 (0.0%) 1.58% $12,597,766 2025-08-14
Q1 2025 Unchanged 5,249,069 0 (0.0%) 1.5% $10,130,703 2025-05-15
Q4 2024 Reduced 5,249,069 -3,200,679 (-37.9%) 3.17% $26,927,724 2025-02-14
Q3 2024 Added 8,449,748 +540 (0.0%) 5.2% $50,022,508 2024-11-14
Q2 2024 Reduced 8,449,208 -254,060 (-2.9%) 4.55% $41,401,119 2024-08-12
Q1 2024 Added 8,703,268 +641,549 (8.0%) 5.02% $62,402,432 2024-05-15
Q4 2023 Added 8,061,719 +2,359,793 (41.4%) 3.51% $36,600,204 2024-02-13
Q3 2023 Unchanged 5,701,926 0 (0.0%) 1.5% $13,456,545 2023-11-14
Q2 2023 Added 5,701,926 +815,310 (16.7%) 2.07% $20,070,780 2023-08-14
Q1 2023 Unchanged 4,886,616 0 (0.0%) 2.35% $18,813,000 2023-05-15
Q4 2022 Added 4,886,616 +1,284,690 (35.7%) 2.82% $25,264,000 2023-02-14
Q3 2022 Added 3,601,926 +360,298 (11.1%) 2.66% $22,260,000 2022-11-14
Q2 2022 Unchanged 3,241,628 0 (0.0%) 1.43% $12,221,000 2022-08-15
Q1 2022 Unchanged 3,241,628 0 (0.0%) 0.86% $8,850,000 2022-05-16
Q4 2021 Unchanged 3,241,628 0 (0.0%) 2.95% $37,246,000 2022-02-14
Q3 2021 Unchanged 3,241,628 0 (0.0%) 3.74% $60,327,000 2021-11-15
Five years are shown. A free account unlocks the complete reported history. Unlock full history

Who else reported the position

245 managers reported ANNEXON INC for Q2 2026.

Managers reporting ANNEXON INC in Q2 2026.
Manager Activity Shares Change % of reported 13F Reported value Tenure
FMR LLC Added 19,518,496 +8,882,848 < 0.01% $111,450,614 24 qtrs
BlackRock Inc Added 13,539,744 +2,601,235 < 0.01% $77,311,938 8 qtrs
Redmile Group LLC Reduced 11,869,877 -2,679,891 4.55% $67,776,998 24 qtrs
STATE STREET CORPORATION Added 9,824,321 +2,905,066 < 0.01% $56,096,873 24 qtrs
BVF INC IL Unchanged 8,698,173 0 1.27% $49,666,568 11 qtrs
Woodline Partners LP Added 6,925,067 +4,587,930 0.12% $39,542,133 17 qtrs
VANGUARD CAPITAL MANAGEMENT LLC Added 6,871,015 +914,426 < 0.01% $39,233,496 2 qtrs
MAK CAPITAL ONE LLC Added 5,862,180 +1,138,137 4.69% $33,473,048 3 qtrs
The Goldman Sachs Group Inc Added 5,825,579 +3,672,699 < 0.01% $33,264,057 23 qtrs
Siren L L C Added 4,458,646 +500,000 0.52% $25,458,869 2 qtrs
Premium adds each manager's conviction percentile across reporting peers.
Filing details and methodology As reported
Report period
June 30, 2026
Filed
August 14, 2026
Filing type
13F-HR
Position type
COM

Voting authority reported

Sole
4,437,731
Shared
0
None
0

“None” means the manager reported no voting authority for those shares on non-routine matters. It does not disclose why and is not evidence of securities lending.

Form 13-F is a delayed quarter-end snapshot of disclosed long Section 13(f) securities. It can be filed up to 45 days after quarter end, excludes short positions and most non-U.S. securities, and does not reveal intra-quarter trading. For options, reported shares and value describe the underlying-share exposure; strike, expiry, premium, and written positions are not disclosed.