IRON MOUNTAIN INC 8-K

What Happened

• Iron Mountain Incorporated filed a Current Report on Form 8-K on March 9, 2026, furnishing Exhibit 99.1, which describes the material U.S. federal income tax considerations relating to the Company’s qualification and taxation as a real estate investment trust (REIT) and the acquisition, ownership and disposition of its stock.
• The new description in Exhibit 99.1 replaces and supersedes prior descriptions to the extent they are inconsistent. The filing also includes an opinion and consent from law firm Sullivan & Worcester LLP (Exhibit 8.1 and 23.1).

Key Details

• Filing date: March 9, 2026 (Form 8-K).
• Main exhibit: 99.1 — Material U.S. Federal Income Tax Considerations for IRM and its stockholders (filed with the 8-K).
• Legal opinion/consent: Sullivan & Worcester LLP provided an opinion on tax matters (Exhibit 8.1) and consent (contained in Exhibit 8.1/23.1).
• The new tax description supersedes any prior descriptions of the Company’s federal tax treatment to the extent of inconsistency.

Why It Matters

• This filing gives shareholders an updated, authoritative explanation of how Iron Mountain’s REIT status may affect federal income tax treatment of dividends, stock sales and other ownership events — important for tax reporting and planning.
• It is not an earnings or operational update, but a legal/tax disclosure; investors should review Exhibit 99.1 and the Sullivan & Worcester opinion and, if needed, consult a tax advisor to understand personal tax implications.