Iron Mountain (IRM) Shares Outstanding (Diluted Average) (2009 - 2026)

Iron Mountain has disclosed Shares Outstanding (Diluted Average) across 17 years of filings, most recently posting $298.8 million for Q1 2026.

• Shares Outstanding (Diluted Average) for Q1 2026 came in at $298.8 million, up 0.53% year-over-year; the trailing twelve-month figure through Mar 2026 was $298.8 million (up 0.53% YoY), and the FY2025 annual result was $297.8 million, up 0.53% from the prior year.
• Shares Outstanding (Diluted Average) came in at $298.8 million for Q1 2026 at Iron Mountain, roughly flat from $297.8 million in the prior quarter.
• In the past five years, Shares Outstanding (Diluted Average) ranged from a high of $298.8 million in Q1 2026 to a low of $291.8 million in Q1 2022.
• The 5-year median for Shares Outstanding (Diluted Average) is $294.3 million (2023), against an average of $294.8 million.
• Across the five-year window, Shares Outstanding (Diluted Average) declined 0.23% in 2024 and rose 1.49% in 2025, its largest moves.
• Iron Mountain's Shares Outstanding (Diluted Average) stood at $292.4 million in 2022, then increased by 0.52% to $294.0 million in 2023, then gained by 0.77% to $296.2 million in 2024, then grew by 0.53% to $297.8 million in 2025, then rose by 0.34% to $298.8 million in 2026.
• The last three Shares Outstanding (Diluted Average) figures came in at $298.8 million (Q1 2026), $297.8 million (Q4 2025), and $298.0 million (Q3 2025), per Business Quant data.