401(k) · DOL Form 5500 · 2022
Iron Mountain Incorporated 401(k) Plan
Data updated 2026-08-25
- $651M
- Total assets Above avg plan size
- 7,917
- Participants Very large workforce
- 98th
- Percentile by assets National rank
- $82,272
- Avg per participant Below avg balance/head
Official DOL plan name: The Iron Mountain Companies 401(k) Plan · Sponsored by Iron Mountain Incorporated · Massachusetts · Transportation & Warehousing
$651M in assets, 7,917 participants
Iron Mountain Incorporated's The Iron Mountain Companies 401(k) Plan reported $651M in total assets and 7,917 participants in its 2022 DOL Form 5500 filing, ranking in the 98th percentile by assets among filed plans. Figures are as reported by the plan sponsor to the Department of Labor, not audited or endorsed by PlainRetire.
- #3,780 in Transportation & Warehousing (3,876 peers)
Coverage in Massachusetts
The Iron Mountain Companies 401(k) Plan covers 7,917 participants in Massachusetts, 12x the typical Massachusetts plan (state average ~659 per filing). Assets: $651M.
- #3,780
- in Transportation & Warehousing (3,876 peers)
- -19.5%
- assets change YoY
- 6.5×
- vs typical plan assets (national mean)
The plan reported a net loss of $169M for the year, a single-year figure driven by markets and benefit payments, not a measure of plan health.
The Iron Mountain Companies 401(k) Plan's outsized position by total assets
The Iron Mountain Companies 401(k) Plan vs every filed plan by assets
End-of-year total assets · plan year 2022 · DOL Form 5500
$651,344,944 Top 2% higher than 98% of 139,123 filed plans
Dashed line + filled bar = this entry, among filed plans.
Source U.S. Department of Labor Form 5500 filings (EBSA) · plan year 2022
The Iron Mountain Companies 401(k) Plan's large-plan peer group by participant headcount
Plan-year 2022 Form 5500 filings with a reported participant count, partitioned by headcount band, not by assets. The Iron Mountain Companies 401(k) Plan lands in the large band (7,917 participants).
Published 5500 schedule card
Filing strip 232588479 · Iron Mountain Incorporated PY 2022 · 401(k)
The Iron Mountain Companies 401(k) Plan · $651M · 7,917 · 98th
- PHOTO $651M
- IND 7,917
- EOY 98th
- 5500 401(k)
- ASSETS near Adm 401(k) and Employee Stock Ownership Plan for Hourly Employees
- PCT ind #3780
Stamps derive from this plan's Form 5500 line items (assets, participants, type, EIN, cohort placement) - not a quality rating of the sponsor. Read with Transportation & Warehousing retirement plans → · Plans in Massachusetts →
The Iron Mountain Companies 401(k) Plan in the asset neighbourhood
Massachusetts filing particulars
| Total Assets (Beginning of Year) | $809M |
|---|---|
| Net Assets (End of Year) | $651M |
| Net Income | -$169M |
| Employer EIN | 232588479 |
| Plan Effective Date | 1988-11-09 |
| Filing Status | FILING RECEIVED |
Sponsor Plan History (Iron Mountain Incorporated)
Sponsor-wide plan assets over time
All Iron Mountain Incorporated plans reported in each filing year
- Latest sponsor-wide plan assets
- $943M 44.79564916988133% vs 2022
- 2024 filing year
| Year | Plans | Participants | Total Assets |
|---|---|---|---|
| 2022 | 1 | 7,917 | $651M |
| 2023 | 1 | 8,643 | $805M |
| 2024 | 1 | 9,146 | $943M |
Nearby 401(k) Plans in Massachusetts
Peer 401(k) plans, same state, same plan type, ranked by total assets.
- Fidelity Retirement Savings Plan $23.0B · 52,036
- Liberty Mutual 401(k) Plan $8.8B · 32,843
- Massachusetts Institute of Technology Supplemental 401(k) Plan $5.8B · 13,690
- Philips North America 401(k) Plan $5.2B · 19,750
- Boston Scientific Corporation 401(k) Retirement Savings Plan $4.9B · 18,359
Scale composition for The Iron Mountain Companies 401(k) Plan
The Iron Mountain Companies 401(k) Plan reports $651M in end-of-year assets across 7,917 participants (0.005% of the $12.3T held by all Form 5500 filers in the national rollup , and 0.008% of 93,925,755 covered participants) - about $82,272 per participant (60% of the national average assets-per-participant) . Net income for plan year 2022 was -$169M.
This plan identity (EIN 232588479, plan #001) has 3 Form 5500 filings on file from 2022 to 2024 , with end-of-year assets moving from $651M to $943M (+44.8%) while covered participants moved from 7,917 to 9,146 . Single-year sparse filers cannot show that trail.
| Plan year | Participants | EOY assets | Filing |
|---|---|---|---|
| 2022 | 7,917 | $651M | This page |
| 2023 | 8,643 | $805M | Open filing |
| 2024 · index core | 9,146 | $943M | Open filing |
The same sponsor also keeps 1 other index-core plan on PlainRetire:
- The Iron Mountain Companies 401(k) Plan (401(k), $943M, 9,146 participants)
The Iron Mountain Companies 401(k) Plan's out-of-state 401(k) peers by assets and headcount
Outside Massachusetts, the nearest 401(k) by assets is Adm 401(k) and Employee Stock Ownership Plan for Hourly Employees in IL ($651M); by covered participants it is Radnet 401(k) Plan in CA (7,919 participants). Same-state nearby plans are listed separately above.
Closest by plan assets
Nearest other-state filings by tot_assets_eoy ($651M here).
- Adm 401(k) and Employee Stock Ownership Plan for Hourly Employees (IL) $651M · 9,395
- Acosta, Inc. 401(k) Retirement Plan (FL) $652M · 21,725
- The Cleveland-Cliffs Steel Corporation Thrift Plan (OH) $652M · 2,539
- The Reynolds and Reynolds Company 401(k) Savings Plan (OH) $652M · 4,522
Similar participant headcount
Nearest other-state filings by covered participants (7,917 participants); asset peers above are excluded.
- Radnet 401(k) Plan (CA) 7,919 · 2 off
- Kellogg Company Savings and Investment Plan (MI) 7,915 · 2 off
- The Communicare Employee's 401(k) Plan (OH) 7,910 · 7 off
- Nnpp Contractor Savings Plan (PA) 7,904 · 13 off
DOL Form 5500 plan year 2022. Asset totals can differ widely at the same headcount; neither axis is a quality rating.