Quick Answer
IRON MOUNTAIN INC reported Shares Outstanding of 295.79 million shares for fiscal year 2025.
IRON MOUNTAIN INC Shares Outstanding — Annual History
| Fiscal Year | Shares Outstanding | YoY Change |
|---|---|---|
| 2025 | 295.79M | +0.7% |
| 2024 | 293.59M | +0.5% |
| 2023 | 292.14M | +0.5% |
| 2022 | 290.83M | +0.4% |
| 2021 | 289.76M | +0.5% |
| 2020 | 288.27M | +0.3% |
| 2019 | 287.30M | +0.3% |
| 2018 | 286.32M | +1.1% |
| 2017 | 283.11M | +7.4% |
| 2016 | 263.68M | +24.8% |
| 2015 | 211.34M | +0.7% |
| 2014 | 209.82M | +9.6% |
| 2013 | 191.43M | +0.7% |
| 2012 | 190.01M | +10.4% |
| 2011 | 172.14M | -14.0% |
| 2010 | 200.06M | -1.7% |
| 2009 | 203.55M | — |
Quarterly Shares Outstanding
| Quarter Ending | Shares Outstanding | YoY | QoQ |
|---|---|---|---|
| September 30, 2025 | 295.50M | +0.7% | +0.1% |
| June 30, 2025 | 295.27M | +0.7% | +0.1% |
| March 31, 2025 | 294.97M | +0.6% | +0.5% |
| December 31, 2024 | 293.59M | +0.5% | +0.1% |
| September 30, 2024 | 293.43M | +0.5% | +0.0% |
| June 30, 2024 | 293.30M | +0.5% | +0.1% |
| March 31, 2024 | 293.09M | +0.5% | +0.3% |
| December 31, 2023 | 292.14M | +0.5% | +0.1% |
- IRON MOUNTAIN INC showed an increase of +0.7% in Shares Outstanding compared to the prior fiscal year.
- Over the 2009–2025 period, IRON MOUNTAIN INC’s shares outstanding has grown by 45.3% (from 203.55 million shares to 295.79 million shares).
- The most recent figure is from IRON MOUNTAIN INC’s fiscal year 2025 report (Form 10-K), filed with the SEC on February 12, 2026.
- All figures are sourced from SEC EDGAR XBRL filings, last verified June 17, 2026.
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