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Nantahala Capital Management, LLC

Position in UPB — Upstream Bio, Inc.

CIK 1472322 New Canaan, CT

Position in UPB

as of Mar 31, 2026 · filed May 15, 2026
Position Value
$3,600,000
-$9,838,462 QoQ
Shares Held
400,000
-19.2% QoQ
Ownership
0.730%
of shares outstanding
% of Portfolio
0.24%
of 13F equity value
Holder Rank
not a current holder
Holding Since
Dec 2024
6 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

Nantahala Capital Management, LLC holds $620,287,047 across 52 Biotechnology names.

# Ticker Company Shares Value (USD) Open

All Filings in UPB

Export CSV
6 filing rows on record
Report Date Value (USD) Shares
2026-03-31 $3,600,000 400,000
2025-12-31 $13,438,462 494,971
2025-09-30 $11,191,404 594,971
2025-06-30 $6,532,781 594,971
2025-03-31 $3,641,222 594,971
2024-12-31 $9,864,000 600,000