Upstream Bio, Inc. (UPB) Insider Ownership

Historic Insider Ownership Trends

As of April 17, 2026, the three largest insider holders of UPB are Upstream Llc Ai (TenPercentOwner, 5.49Mn shares), Upstream Llc Ai (TenPercentOwner, 5.49Mn shares), Erez Chimovits (Director, 4.55Mn shares).

Top Direct Holders

Insider ownership data is derived from the last 60 months of Form 4 SEC filings.
Holder Position Shares (Direct) Shares (Indirect) Report Date
Upstream Llc Ai - 5,494,410 0 17 Oct, 2024
Upstream Llc Ai - 5,494,410 0 17 Oct, 2024
Erez Chimovits - 0 4,554,873 17 Oct, 2024
Advisors Llc Orbimed - 0 4,554,873 17 Oct, 2024
Biomedical Innovation Master Investors (Cayman) Ii L.P. Wellington - 894,733 0 15 Oct, 2024
Everett Rand Sutherland Chief Executive Officer 72,907 0 17 Mar, 2026
Aaron Deykin Chief Medical Officer 32,687 0 17 Mar, 2026
Michael Gray Cfo And Coo 29,648 0 17 Mar, 2026
Adam Houghton Chief Business Officer 24,301 0 17 Mar, 2026
Allison Ambrose General Counsel 16,525 0 17 Mar, 2026

* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.

Recent Insider Transactions

Detailed insider trading activity based on Form 4 SEC filings.
Download Data
Transaction Date Insider Name Security Class Transaction Type Shares Traded Price Shares Remaining Ownership Code
16 Mar, 2026 Michael Gray Common Stock D 852 $9.29 29,648 D S
16 Mar, 2026 Everett Rand Sutherland Common Stock D 2,093 $9.29 72,907 D S
16 Mar, 2026 Allison Ambrose Common Stock D 475 $9.29 16,525 D S
16 Mar, 2026 Adam Houghton Common Stock D 699 $9.29 24,301 D S
16 Mar, 2026 Aaron Deykin Common Stock D 894 $9.29 32,687 D S
02 Jan, 2026 Adam Houghton Common Stock A 25,000 $0.00 25,000 D A
02 Jan, 2026 Allison Ambrose Common Stock A 17,000 $0.00 17,000 D A
02 Jan, 2026 Michael Gray Common Stock A 30,500 $0.00 30,500 D A
02 Jan, 2026 Aaron Deykin Common Stock A 32,000 $0.00 33,581 D A
02 Jan, 2026 Everett Rand Sutherland Common Stock A 75,000 $0.00 75,000 D A
02 Jan, 2026 Michael Gray Stock Option (Right to Buy) A 91,500 $0.00 91,500 D A
02 Jan, 2026 Everett Rand Sutherland Stock Option (Right to Buy) A 225,000 $0.00 225,000 D A
02 Jan, 2026 Adam Houghton Stock Option (Right to Buy) A 75,000 $0.00 75,000 D A
02 Jan, 2026 Allison Ambrose Stock Option (Right to Buy) A 51,000 $0.00 51,000 D A
02 Jan, 2026 Aaron Deykin Stock Option (Right to Buy) A 96,000 $0.00 96,000 D A
10 Jun, 2025 Ronald C Jr Renaud Stock Option (Right to Buy) A 17,096 $0.00 17,096 D A
10 Jun, 2025 Liam Ratcliffe Stock Option (Right to Buy) A 17,096 $0.00 17,096 D A
10 Jun, 2025 Harold Edward Fleming Stock Option (Right to Buy) A 17,096 $0.00 17,096 D A
10 Jun, 2025 Erez Chimovits Stock Option (Right to Buy) A 17,096 $0.00 17,096 D A
10 Jun, 2025 Daniella Beckman Stock Option (Right to Buy) A 17,096 $0.00 17,096 D A