Generation Bio

GBIO • NASDAQ

Generation Bio is a biotechnology company in the healthcare sector on NASDAQ, led by Geoff McDonough, with a market cap of $36.6M. As of Q3 2025, 59% of shares are held by 37 institutional investors, with Atlas Venture Life Science Advisors, LLC as the largest holder at 12.29%.

CEOGeoff McDonough

Market Cap$36.6M

Biotechnology

Healthcare

Employees174.0

Websitegenerationbio.com

Country

United States of America

Overview

Overview of institutional ownership in GBIO as of Q3 2025 with a market cap of $41.2M

All Institutions

Institutions: 37
Value Held: $24.2M
Shares Held: 4.0M
Avg Position: $654.0K
Median Position: $163.5K

Hedge Funds

Hedge Funds: 8
Value Held: $5.1M
Shares Held: 838.5K
Avg Position: $641.4K
Median Position: $442.3K

Ownership Breakdown

Institutional (non-HF)

46.25%

$19.1M

Hedge Funds

12.45%

$5.1M

Retail & Other

41.3%

$17.0M

Based on market cap of $41.2M as of Q3 2025. Institutional (non-HF) excludes hedge funds to avoid double counting.

Biggest Investors

Institutions with the largest positions in GBIO as of Q3 2025

Institution	Key People	Position Value	Ownership	Owned Since	Total AUM (Long)
A Atlas Venture Life Science Advisors, LLC Institution	-	$5.1M 0.67% of portfolio	12.29% 827.9K shares	Q4 2021 Held for 3y 11m	$752.6M
PRICE T ROWE ASSOCIATES INC /MD/ Long Only Manager	Robert W Sharps President	$3.5M 0.00% of portfolio	8.56% 576.8K shares	Q2 2020 Held for 5y 5m	$912.31B
RENAISSANCE TECHNOLOGIES LLC Hedge Fund•Quant	Peter Fitzhugh Brown CEO	$2.1M 0.00% of portfolio	5.11% 344.3K shares	Q2 2021 Held for 4y 5m	$75.8B
S Siren, L.L.C. Institution	-	$1.8M 0.08% of portfolio	4.41% 296.9K shares	Q3 2024 Held for 1y 2m	$2.4B
VANGUARD GROUP INC Institution	Salim Ramji CEO	$1.4M 0.00% of portfolio	3.41% 229.8K shares	Q2 2020 Held for 5y 5m	$6.69T
Marshall Wace LLP Institution	Diana Lj Harrison President	$1.3M 0.00% of portfolio	3.24% 218.5K shares	Q3 2025 Held for 2 months	$90.3B
B BAKER BROS. ADVISORS LP Hedge Fund•Sector	Scott Lawrence Lessing President	$1.2M 0.01% of portfolio	2.89% 194.5K shares	Q1 2024 Held for 1y 8m	$10.8B
MORGAN STANLEY RIA/Wealth	Jed Finn CEO	$1.0M 0.00% of portfolio	2.44% 164.3K shares	Q3 2020 Held for 5y 2m	$1.65T
UBS Group AG Institution	Sergio P. Ermotti CEO	$910.2K 0.00% of portfolio	2.21% 148.7K shares	Q2 2020 Held for 5y 5m	$511.54B
ACADIAN ASSET MANAGEMENT LLC Long Only Manager	Gillian Morna Therese Savage CEO	$780.3K 0.00% of portfolio	1.89% 127.5K shares	Q4 2023 Held for 1y 11m	$51.5B

Net Capital Flow

Institutional buying and selling activity for GBIO in Q3 2025

Traded: +$1.0M
Buyers: 18
Sellers: 43
Total Bought: +$3.9M
Total Sold: −$2.9M
Avg Position: $378.1K

Biggest Buyers

Institution	Net Bought	Current Position
Marshall Wace LLP Institution	+$1.3M +218.5K shares	$1.3M 218.5K shares
C CANTOR FITZGERALD, L. P. Institution	+$605.9K +99.0K shares	$605.9K 99.0K shares
RENAISSANCE TECHNOLOGIES LLC Hedge Fund•Quant	+$527.5K +86.2K shares	$2.1M 344.3K shares
MORGAN STANLEY RIA/Wealth	+$446.7K +73.0K shares	$1.0M 164.3K shares
UBS Group AG Institution	+$368.6K +60.2K shares	$910.2K 148.7K shares
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	+$171.2K +28.0K shares	$288.8K 47.2K shares
A ADAR1 Capital Management, LLC Hedge Fund•Long/Short	+$135.5K +22.1K shares	$135.5K 22.1K shares
FMR LLC Institution	+$79.8K +-221.5K shares	$79.8K 13.0K shares
GOLDMAN SACHS GROUP INC Institution	+$74.5K +12.2K shares	$725.7K 118.6K shares
X XTX Topco Ltd Institution	+$69.4K +11.3K shares	$69.4K 11.3K shares

Biggest Sellers

Institution	Net Sold	Current Position
PRICE T ROWE ASSOCIATES INC /MD/ Long Only Manager	−$1.6M −269.5K shares	$3.5M 576.8K shares
B BlackRock, Inc. Institution	−$343.0K −56.0K shares	$367.9K 60.1K shares
Militia Capital Partners, LP Hedge Fund•Long/Short	−$173.6K −54.2K shares	Sold Off 0 shares
S Squarepoint Ops LLC Hedge Fund•Quant	−$165.9K −51.8K shares	Sold Off 0 shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	−$79.8K −24.9K shares	Sold Off 0 shares
SCHWAB CHARLES INVESTMENT MANAGEMENT INC Long Only Manager	−$75.8K −23.7K shares	Sold Off 0 shares
TWO SIGMA ADVISERS, LLC Hedge Fund•Multi-Strategy	−$61.3K −19.1K shares	Sold Off 0 shares
MILLENNIUM MANAGEMENT LLC Hedge Fund•Multi-Strategy	−$53.9K −8.8K shares	$595.8K 97.4K shares
Y Y-Intercept Ltd Institution	−$47.4K −14.8K shares	Sold Off 0 shares
T TD ASSET MANAGEMENT INC Institution	−$45.0K −7.4K shares	$163.5K 26.7K shares

Entry and Exit Activity

Institutions that initiated new positions or completely exited GBIO in Q3 2025

New Positions: 5
New Value: $807.3K
Exited Positions: 25
Exited Value: $810.7K

New Positions

Institution	Position Value
C CANTOR FITZGERALD, L. P. Institution	$605.9K 99.0K shares
A ADAR1 Capital Management, LLC Hedge Fund•Long/Short	$135.5K 22.1K shares
S Shay Capital LLC Institution	$63.7K 10.4K shares
Rockefeller Capital Management L.P. Long Only Manager	$2.1K 350.0 shares
O Optiver Holding B.V. Institution	$31.0 5.0 shares

Exited Positions

Institution	Previous Position
Militia Capital Partners, LP Hedge Fund•Long/Short	$173.6K 54.2K shares
S Squarepoint Ops LLC Hedge Fund•Quant	$165.9K 51.8K shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	$79.8K 24.9K shares
SCHWAB CHARLES INVESTMENT MANAGEMENT INC Long Only Manager	$75.8K 23.7K shares
TWO SIGMA ADVISERS, LLC Hedge Fund•Multi-Strategy	$61.3K 19.1K shares
Y Y-Intercept Ltd Institution	$47.4K 14.8K shares
BARCLAYS PLC Institution	$36.8K 1.1K shares
Aegis Wealth Management LLC RIA/Wealth	$36.0K 8.9K shares
Callan Family Office, LLC Family Office	$22.3K 7.0K shares
AQR CAPITAL MANAGEMENT LLC Hedge Fund•Multi-Strategy	$20.4K 6.4K shares

Options Activity

Institutions with the largest Call and Put options positions in GBIO as of Q3 2025

Call Positions: 1
Call Value: -
Put Positions: 0
Put Value: -

Call Positions

Institution	Position Value
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	- - contracts

Put Positions

Institution	Position Value
No put positions found

Most Committed Institutions

Institutions with GBIO as the highest % of their portfolio as of Q3 2025

Institution	Key People	Portfolio Weight	Ownership	Owned Since	Total AUM (Long)
A Atlas Venture Life Science Advisors, LLC Institution	-	0.67% $5.1M	12.29% 827.9K shares	Q4 2021 Held for 3y 11m	$752.6M
YIHENG CAPITAL LLC Hedge Fund•Long/Short	Yuanshan Guo Managing Partner	0.22% $645.8K	1.57% 105.5K shares	Q2 2021 Held for 4y 5m	$297.8M
S Siren, L.L.C. Institution	-	0.08% $1.8M	4.41% 296.9K shares	Q3 2024 Held for 1y 2m	$2.4B
P Palo Alto Investors, LLC Hedge Fund•Long/Short	Angela Elizabeth Nguyen-Dinh CCO	0.02% $92.1K	0.22% 15.0K shares	Q2 2024 Held for 1y 5m	$540.4M
A ADAR1 Capital Management, LLC Hedge Fund•Long/Short	Daniel Pawel Schneeberger Managing Partner	0.01% $135.5K	0.33% 22.1K shares	Q3 2025 Held for 2 months	$993.7M
C CANTOR FITZGERALD, L. P. Institution	-	0.01% $605.9K	1.47% 99.0K shares	Q3 2025 Held for 2 months	$5.1B
S Shay Capital LLC Institution	-	0.01% $63.7K	0.15% 10.4K shares	Q3 2025 Held for 2 months	$548.9M
B BAKER BROS. ADVISORS LP Hedge Fund•Sector	Scott Lawrence Lessing President	0.01% $1.2M	2.89% 194.5K shares	Q1 2024 Held for 1y 8m	$10.8B
X XTX Topco Ltd Institution	-	0.00% $69.4K	0.17% 11.3K shares	Q2 2023 Held for 2y 5m	$1.9B
RENAISSANCE TECHNOLOGIES LLC Hedge Fund•Quant	Peter Fitzhugh Brown CEO	0.00% $2.1M	5.11% 344.3K shares	Q2 2021 Held for 4y 5m	$75.8B

Hedge Fund Spotlight

Discover hedge funds investing in GBIO

ADAR1 Capital Management, LLC

Hedge Fund • Long/Short

Portfolio ManagerDaniel Pawel Schneeberger

Portfolio Value: $993.7M
Positions: 191
Last Reported: Q3 2025

Sector Allocation

Position in Generation Bio

Market Value: $135.5K
Shares Held: 22.1K
Portfolio Weight: 0.01%
Owned Since: 2025-Q3

Top Holding	Sector	Market Value	Weight
1 ABVX Abivax ABVX	Unknown Unknown	$114.7M	11.54%
2 Keros Therapeutics KROS	Biotechnology Healthcare	$85.3M	8.58%
3 Protagonist Therapeutics PTGX	Biotechnology Healthcare	$65.7M	6.61%

View full profile

Generation Bio

Overview

All Institutions

Hedge Funds

Ownership Breakdown

Biggest Investors

Net Capital Flow

Biggest Buyers

Biggest Sellers

Entry and Exit Activity

New Positions

Exited Positions

Options Activity

Call Positions

Put Positions

Most Committed Institutions

Hedge Fund Spotlight

Position in Generation Bio

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