Question 1

Which hedge funds and institutional investors hold BIIB?

Accepted Answer

StonkWhisper tracks 13F filings submitted to the SEC by institutional investment managers with over $100 million in assets. The whale tracker for BIIB shows which major funds hold positions, their portfolio weight, share counts, and how those positions changed quarter over quarter.

Question 2

What does conviction level mean for BIIB whale holdings?

Accepted Answer

Conviction level reflects how significant BIIB is within a fund's overall portfolio. A high-conviction position means the manager has allocated a large percentage of their portfolio to BIIB, suggesting strong directional confidence in the stock.

Question 3

How current is the whale data for BIIB?

Accepted Answer

Institutional 13F filings are required within 45 days of each calendar quarter end (March 31, June 30, September 30, December 31). StonkWhisper processes filings as they are published on SEC EDGAR, so data reflects the most recently reported quarter.

Question 4

What do quarter-over-quarter changes tell me about BIIB?

Accepted Answer

QoQ changes for BIIB show whether institutional managers are increasing, decreasing, initiating, or exiting their positions. New positions and significant increases can signal growing institutional conviction, while exits or decreases may indicate waning confidence.

Manager	Shares	Value	% of Portfolio	Manager AUM
PRIMECAP	14.8M	$2.7B	2.1%	$127.0B
State Street	7.2M	$1.3B	0.0%	$2896.4B
Point72	809.6K	$148.4M	0.2%	$78.1B
Balyasny	650.0K	$119.2M	0.2%	$77.1B
Geode Capital	471.3K	$86.4M	0.0%	$1607.5B
Adage Capital	333.5K	$61.1M	0.1%	$64.8B
Fisher Investments	312.6K	$57.3M	0.0%	$294.9B
Citadel	299.9K	$55.0M	0.0%	$618.5B
Gotham Asset	298.4K	$54.7M	0.2%	$32.7B
Renaissance Tech	203.4K	$37.3M	0.1%	$63.9B
Hudson Bay	201.4K	$36.9M	0.1%	$29.0B
DFA	197.3K	$36.2M	0.0%	$481.4B
ExodusPoint	152.0K	$27.9M	0.2%	$12.4B
American Century	104.8K	$19.2M	0.0%	$194.3B
Millennium	103.9K	$19.0M	0.0%	$240.3B
Citadel	97.4K	$17.9M	0.0%	$618.5B
Millennium	94.0K	$17.2M	0.0%	$240.3B
Marshall Wace	93.4K	$17.1M	0.0%	$100.4B
Citadel	92.7K	$17.0M	0.0%	$618.5B
Millennium	83.9K	$15.4M	0.0%	$240.3B
Glenview Capital	57.0K	$10.5M	0.3%	$4.0B
Schonfeld	48.8K	$9.0M	0.1%	$14.2B
Wellington	26.4K	$4.8M	0.0%	$535.5B
Northern Trust	17.4K	$3.2M	0.0%	$756.6B
DE Shaw	15.5K	$2.8M	0.0%	$166.3B
Man Group	14.7K	$2.7M	0.0%	$55.1B
Gabelli	14.1K	$2.6M	0.0%	$14.8B
Two Sigma	9.4K	$1.7M	0.0%	$123.9B
DE Shaw	6.4K	$1.2M	0.0%	$166.3B
Point72	4.7K	$862K	0.0%	$78.1B
GGH	4.6K	$836K	0.0%	$8.3B
Winton	3.3K	$604K	0.0%	$2.9B
Horizon Kinetics	2.9K	$524K	0.0%	$9.2B
Marshall Wace	2.5K	$458K	0.0%	$100.4B
PDT Partners	2.3K	$430K	0.0%	$1.7B
Fidelity (FMR)	1.8K	$330K	—	$1898.4B
Marshall Wace	1.3K	$238K	0.0%	$100.4B
BlackRock	1.3K	$233K	—	$5723.5B
Tudor	1.1K	$202K	0.0%	$53.9B
Neuberger Berman (Eisman)	472	$87K	0.0%	$131.4B
LSV	333.7K	$61K	0.1%	$46.4M
Acadian	248.5K	$46K	0.1%	$70.5M
Franklin Templeton	87	$16K	—	$408.3B
AQR Capital	16	$3K	—	$218.4B
Kayne Anderson	0	$180	—	$34.0B

BIIB

Who Holds BIIB

Changes This Quarter