Quick Answer
Upstream Bio, Inc. reported Shares Outstanding of 54.24 million shares for fiscal year 2025.
Upstream Bio, Inc. Shares Outstanding — Annual History
| Fiscal Year | Shares Outstanding | YoY Change |
|---|---|---|
| 2025 | 54.24M | +1.2% |
| 2024 | 53.60M | +1691.3% |
| 2023 | 2.99M | — |
Quarterly Shares Outstanding
| Quarter Ending | Shares Outstanding | YoY | QoQ |
|---|---|---|---|
| September 30, 2025 | 54.00M | +1684.8% | +0.4% |
| June 30, 2025 | 53.80M | — | +0.3% |
| March 31, 2025 | 53.64M | — | +0.1% |
| December 31, 2024 | 53.60M | +1691.3% | +1671.7% |
| September 30, 2024 | 3.03M | — | +1.1% |
| December 31, 2023 | 2.99M | — | — |
- Upstream Bio, Inc. showed an increase of +1.2% in Shares Outstanding compared to the prior fiscal year.
- Over the 2023–2025 period, Upstream Bio, Inc.’s shares outstanding has grown by 1712.5% (from 2.99 million shares to 54.24 million shares).
- The most recent figure is from Upstream Bio, Inc.’s fiscal year 2025 report (Form 10-K), filed with the SEC on March 26, 2026.
- All figures are sourced from SEC EDGAR XBRL filings, last verified June 17, 2026.
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