Spero Therapeutics (SPRO) Shares Outstanding (Diluted Average) (2021 - 2026)

Spero Therapeutics (SPRO) has 6 years of Shares Outstanding (Diluted Average) data on file, last reported at $57.3 million in Q1 2026.

• For the quarter ending Q1 2026, Shares Outstanding (Diluted Average) rose 3.44% year-over-year to $57.3 million; the trailing twelve-month figure through Mar 2026 stood at $57.3 million (up 3.44% YoY), and the FY2025 full-year result was $59.0 million, up 9.26% from the prior year.
• Shares Outstanding (Diluted Average) for Q1 2026 stood at $57.3 million, down from $59.0 million in the prior quarter.
• Across five years, Shares Outstanding (Diluted Average) topped out at $59.0 million in Q4 2025 and bottomed at $32.6 million in Q1 2022.
• The 5-year median for Shares Outstanding (Diluted Average) is $53.5 million (2024), against an average of $49.8 million.
• The widest annual swing landed in 2023, when Shares Outstanding (Diluted Average) jumped 61.09%; it then climbed 1.9% in 2024.
• A 5-year view of Shares Outstanding (Diluted Average) shows it stood at $37.6 million in 2022, then surged by 40.98% to $53.0 million in 2023, then grew by 1.98% to $54.0 million in 2024, then advanced by 9.26% to $59.0 million in 2025, then slipped by 2.98% to $57.3 million in 2026.
• The last three Shares Outstanding (Diluted Average) figures came in at $57.3 million (Q1 2026), $59.0 million (Q4 2025), and $55.9 million (Q3 2025), per Business Quant data.

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