SuperworthSpero Therapeutics shares outstanding SPRO
Diluted shares outstanding, averaged over each quarter, from 2016.
- Latest quarter, to Jun 30, 2026
- 58M
- On a year earlier
- +3.5%
- more shares
Spero Therapeutics had 58M diluted shares outstanding on average in Q2 FY26, the quarter to Jun 30, 2026.
That is 3.5% more than a year earlier, so each share owns a little less of the company.
Shares outstanding over time
Fiscal year by fiscal year
| Fiscal year | Shares, fourth quarter | Change |
|---|---|---|
| FY2025 | 59.5M | +9% |
| FY2024 | 54.5M | +2% |
| FY2023 | 53.3M | +9% |
| FY2022 | 48.7M | +51% |
| FY2021 | 32.3M | +18% |
| FY2020 | 27.4M | +44% |
| FY2019 | 19.1M | +7% |
| FY2018 | 17.7M | +91% |
| FY2017 | 9.3M | +2758% |
| FY2016 | 324.5K | n/a |
Each fiscal year is the twelve months to its fourth quarter, shown as the fourth quarter's average share count.
Quarter by quarter
| Quarter | Ended | Shares outstanding | On a year earlier |
|---|---|---|---|
| Q2 FY26 | 58M | +3% | |
| Q1 FY26 | 57.3M | +3% | |
| Q4 FY25 | 59.5M | +9% | |
| Q3 FY25 | 56.3M | +4% | |
| Q2 FY25 | 56M | +4% | |
| Q1 FY25 | 55.4M | +3% | |
| Q4 FY24 | 54.5M | +2% | |
| Q3 FY24 | 54.1M | +3% | |
| Q2 FY24 | 54M | +3% | |
| Q1 FY24 | 53.5M | +2% | |
| Q4 FY23 | 53.3M | +9% | |
| Q3 FY23 | 52.7M | +47% |
What the shares outstanding tells you
Diluted shares outstanding, averaged over the period. Fewer shares means each one owns more of the company.
A falling count usually means buybacks. A rising one means stock pay, acquisitions paid in shares or new shares sold.
More on Spero Therapeutics
Valuation data, not investment advice. Prices as of . Reported figures come from the company's filings with the SEC.