Spero Therapeutics (SPRO) Shares Outstanding (2016 - 2026)

Spero Therapeutics (SPRO) has 11 years of Shares Outstanding data on file, last reported at $57.9 million in Q1 2026.

• For the quarter ending Q1 2026, Shares Outstanding rose 3.56% year-over-year to $57.9 million; the trailing twelve-month figure through Mar 2026 stood at $57.9 million (up 3.56% YoY), and the FY2025 full-year result was $56.4 million, up 3.34% from the prior year.
• Shares Outstanding for Q1 2026 stood at $57.9 million, up from $56.4 million in the prior quarter.
• Across five years, Shares Outstanding topped out at $57.9 million in Q1 2026 and bottomed at $2.3 million in Q2 2022.
• The 5-year median for Shares Outstanding is $53.9 million (2024), against an average of $49.5 million.
• The widest annual swing landed in 2022, when Shares Outstanding surged 1530.01%; it then increased 1.04% in 2023.
• A 5-year view of Shares Outstanding shows it stood at $52.5 million in 2022, then increased by 1.04% to $53.0 million in 2023, then rose by 3.01% to $54.6 million in 2024, then increased by 3.34% to $56.4 million in 2025, then gained by 2.62% to $57.9 million in 2026.
• The last three Shares Outstanding figures came in at $57.9 million (Q1 2026), $56.4 million (Q4 2025), and $56.3 million (Q3 2025), per Business Quant data.

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