TickerFacts.

Upstream Bio, Inc. (UPB): Shares Outstanding

Annual figures by period end, from SEC filings.

54.24M
As of 2025-12-31
54.77M
As of 2026-06-30
2023-12-31: 2.99M2024-12-31: 53.60M2025-12-31: 54.24M54.24M
2023-12-31 Shares Outstanding (shares) 2025-12-31
Period endedShares OutstandingChange YoYSource filing
2025-12-3154.24M+1.2%2026-03-26, Balance as of period end
2024-12-3153.60Mn/m2026-03-26, Balance as of period end
2023-12-312.99Mn/a2025-03-12, Balance as of period end