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Bain Capital Life Sciences Investors, LLC

Position in UPB — Upstream Bio, Inc.

CIK 1703031 Boston, MA

Position in UPB

as of Jun 30, 2026 · filed Aug 14, 2026
Position Value
$4,158,567
-$3,646,332 QoQ
Shares Held
600,949
-30.7% QoQ
Ownership
1.10%
of shares outstanding
% of Portfolio
0.25%
of 13F equity value
Holder Rank
#19
of 148 holders
Holding Since
Dec 2024
7 quarters on record
Voting authority Sole 100% Shared 0% None 0%

Common Shares in UPB Over Time

Shares Held

Position Value (USD)

Position in Biotechnology

Healthcare · as of Jun 30, 2026

Bain Capital Life Sciences Investors, LLC holds $1,318,022,438 across 17 Biotechnology names. UPB ranks #17 (0.3% of the industry book) .

# Ticker Company Shares Value (USD) Open

All Filings in UPB

Export CSV
7 filing rows on record
Report Date Value (USD) Shares
2026-06-30 $4,158,567 600,949
2026-03-31 $7,804,899 867,211
2025-12-31 $36,097,119 1,329,544
2025-09-30 $45,887,709 2,439,538
2025-06-30 $26,786,127 2,439,538
2025-03-31 $14,047,370 2,295,322
2024-12-31 $37,735,093 2,295,322