Cyclerion Therapeutics, Inc. (CYCN) Institutional Ownership

Institutions by Trading Activity

3,225,000Shares Outstanding

296,255Shares held by institutions

$879,877Value of institutional holdings

9.19%Institutional ownership %

37.64%Shares Changed QoQ

19No. of institutional investors

Cyclerion Therapeutics, Inc. (NASDAQ:CYCN) has 19 institutional investors that have filed 13F reports for the period ending December 2025.

Their combined ownership stood at 9.2% of outstanding shares in December 2025, up from 8.0% in September 2025.
They increased total shares held in CYCN by 37.64% quarter over quarter, and investors in Cyclerion Therapeutics decreased 5.0% from a year ago.
During the quarter, 9 of these 19 funds increased positions in CYCN, 3 reduced exposure, and 7 held steady.
Combined, these investors held 296.26K shares in CYCN for December 2025, up by 81.02K shares quarter on quarter, and down 87.01K shares year over year.
As of December 31, 2025, Siren, L.L.C. held the largest stake in Cyclerion Therapeutics with 115.6K shares, accounting for 3.58% of total shares outstanding.
The most significant purchases of CYCN for the quarter ending December 2025 came from TWO SIGMA ADVISERS, LP (28.3K), TWO SIGMA INVESTMENTS, LP (28.26K), XTX Topco Ltd (10.03K), Citigroup Inc (8.2K), GEODE CAPITAL MANAGEMENT, LLC (6.14K).
Top sellers of CYCN stock for the quarter ending December 2025 included Morgan Stanley (648), Siren, L.L.C. (552), FMR LLC (6).
According to Business Quant data, leading holders of CYCN for December 2025 are Siren, L.L.C. (115.6K), GEODE CAPITAL MANAGEMENT, LLC (43.3K), TWO SIGMA INVESTMENTS, LP (41.56K), TWO SIGMA ADVISERS, LP (28.3K), VANGUARD GROUP INC (23.49K), BlackRock, Inc. (16.8K), XTX Topco Ltd (10.03K), Citigroup Inc (8.2K), FMR LLC (4.74K), Tower Research Capital LLC (TRC) (3.15K).

296,255 Total Shares Held

Rows:

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
Siren, L.L.C.	31 Dec, 2025	115,603	-552	-0.48%	$146,816.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	43,302	6,144	16.53%	$55,006.00
TWO SIGMA INVESTMENTS, LP	31 Dec, 2025	41,555	28,262	212.61%	$52,775.00
TWO SIGMA ADVISERS, LP	31 Dec, 2025	28,300	28,300	0.00%	$35,941.00
VANGUARD GROUP INC	31 Dec, 2025	23,490	0	0.00%	$29,832.00
BlackRock, Inc.	31 Dec, 2025	16,797	0	0.00%	$21,332.00
XTX Topco Ltd	31 Dec, 2025	10,027	10,027	0.00%	$12,734.00
Citigroup Inc	31 Dec, 2025	8,204	8,204	0.00%	$10,419.00
FMR LLC	31 Dec, 2025	4,740	-6	-0.13%	$6,020.00
Tower Research Capital LLC (TRC)	31 Dec, 2025	3,154	826	35.48%	$4,006.00
UBS Group AG	31 Dec, 2025	376	327	667.35%	$478.00
GROUP ONE TRADING LLC	31 Dec, 2025	192	0	0.00%	$244.00
OSAIC HOLDINGS, INC.	31 Dec, 2025	130	0	0.00%	$165.00
Bank Of America Corp /De/	31 Dec, 2025	107	63	143.18%	$136.00
MAI Capital Management	31 Dec, 2025	100	0	0.00%	$127.00
Activest Wealth Management	31 Dec, 2025	100	0	0.00%	$127.00
WHI TRUST Co LLC	31 Dec, 2025	72	72	0.00%	$91.00
BNP PARIBAS FINANCIAL MARKETS	31 Dec, 2025	5	0	0.00%	$6.00
Morgan Stanley	31 Dec, 2025	1	-648	-99.85%	$2.00