CSS LLC/IL

Position in BIIB — Biogen Inc.

CIK 1103646 CHICAGO, IL

Back to BIIB Full portfolio

Position in BIIB

as of Jun 30, 2026 · filed Aug 14, 2026 Compact

Position Value

$622,252

+$123,595 QoQ

Shares Held

2,880

+5.9% QoQ

Ownership

0.002%

of shares outstanding

% of Portfolio

0.09%

of 13F equity value

Holder Rank

#535

of 1,036 holders

Holding Since

Mar 2020

17 quarters on record

Voting authority Sole 100% Shared 0% None 0%

Common Shares in BIIB Over Time

Shares Held

Position Value (USD)

Derivatives in BIIB

reported options exposure · as of Dec 31, 2022

CallValue

$4,679,948

CallShares

16,900

PutValue

PutShares

Notional value of option positions as reported on Form 13F. Calls and puts are disclosed separately and do not net against the common-share stake above.

Position in Drug Manufacturers - General

Healthcare · as of Jun 30, 2026

CSS LLC/IL holds $6,263,567 across 6 Drug Manufacturers - General names. BIIB ranks #6 (9.9% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	BMY	Bristol Myers Squibb Co	32,320	$1,862,278
2	MRK	Merck & Co., Inc.	10,210	$1,311,985
3	SNY	Sanofi	22,970	$979,900
4	PFE	Pfizer Inc	34,351	$827,172
5	OGN	Organon & Co.	48,743	$659,980
6	BIIB	Biogen Inc. This page	2,880	$622,252

All Filings in BIIB

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32 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-06-30	$622,252	2,880	+5.9%	Shares	Sole	2026-08-14
2026-03-31	$498,657	2,720	-55.3%	Shares	Sole	2026-05-15
2025-12-31	$1,070,019	6,080	-21.5%	Shares	Sole	2026-02-17
2025-09-30	$1,085,620	7,750	+12.0%	Shares	Sole	2025-11-13
2025-06-30	$869,082	6,920	+85.5%	Shares	Sole	2025-08-14
2025-03-31	$510,413	3,730	-41.5%	Shares	Sole	2025-05-15
2022-12-31	$4,679,948	16,900	-28.4%	Call	Sole	2023-02-14
2022-09-30	$6,301,200	23,600	+124.8%	Call	Sole	2022-11-14
2022-09-30	$8,277,000	31,000	+181.8%	Put	Sole	2022-11-14
2022-09-30	$1,702,926	6,378	+127.8%	Shares	Sole	2022-11-14
2022-03-31	$2,211,300	10,500	-77.8%	Call	Sole	2022-05-16
2021-12-31	$671,776	2,800	+52.8%	Shares	Sole	2022-02-14
2021-12-31	$11,372,208	47,400	+256.4%	Call	Sole	2022-02-14
2021-12-31	$2,639,120	11,000	+378.3%	Put	Sole	2022-02-14
2021-09-30	$650,877	2,300	-80.0%	Put	Sole	2021-11-15
2021-09-30	$3,763,767	13,300	-46.8%	Call	Sole	2021-11-15
2021-06-30	$3,982,105	11,500	-55.4%	Put	Sole	2021-08-16
2021-06-30	$8,656,750	25,000	-76.1%	Call	Sole	2021-08-16
2021-06-30	$634,366	1,832	-83.5%	Shares	Sole	2021-08-16
2021-03-31	$29,233,875	104,500	-49.0%	Call	Sole	2021-05-17
2021-03-31	$3,111,099	11,121	-26.3%	Shares	Sole	2021-05-17
2020-12-31	$50,196,300	205,000	+329.8%	Call	Sole	2021-02-16
2020-12-31	$3,694,692	15,089	-21.4%	Shares	Sole	2021-02-16
2020-12-31	$6,317,388	25,800	+7.5%	Put	Sole	2021-02-16
2020-09-30	$6,808,320	24,000	-29.4%	Put	Sole	2020-11-16
2020-09-30	$13,531,536	47,700	+5862.5%	Call	Sole	2020-11-16
2020-06-30	$5,135,889	19,196	+2241.0%	Shares	Sole	2020-08-14
2020-06-30	$214,040	800	-71.4%	Call	Sole	2020-08-14
2020-06-30	$9,096,700	34,000	+41.7%	Put	Sole	2020-08-14
2020-03-31	$7,593,120	24,000	—	Put	Sole	2020-05-15
2020-03-31	$885,864	2,800	—	Call	Sole	2020-05-15
2020-03-31	$259,431	820	—	Shares	Sole	2020-05-15
No filing history on record for this holder in this stock.