401(k) · DOL Form 5500 · 2023
Iron Mountain Incorporated 401(k) Plan
Data updated 2026-08-11
- $805M
- Total assets
- 8,643
- Participants
- 98th
- Percentile by assets
- $93,093
- Avg per participant
Official DOL plan name: The Iron Mountain Companies 401(k) Plan · Sponsored by Iron Mountain Incorporated · Pennsylvania · Transportation & Warehousing
$805M in assets, 8,643 participants
Iron Mountain Incorporated's The Iron Mountain Companies 401(k) Plan reported $805M in total assets and 8,643 participants in its 2023 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.
- 98th percentile by assets (of 127,072 plans)
- #3,272 in Transportation & Warehousing (3,362 peers)
Coverage in Pennsylvania
The Iron Mountain Companies 401(k) Plan covers 8,643 participants in Pennsylvania, 11x the typical Pennsylvania plan (state average ~822 per filing). Assets: $805M.
- $805M
- total plan assets (2023 EOY)
- 8,643
- covered participants
- 98th
- percentile by assets (of 127,072 plans)
- $93,093
- avg assets per participant
What changed between DOL Form 5500 filings
plan year 2022 → plan year 2023
- The Iron Mountain Companies 401(k) Plan reported net income rose from -$169M in the plan year 2022 filing to $151M in the plan year 2023 filing.
- The Iron Mountain Companies 401(k) Plan end-of-year assets rose from $651M in the plan year 2022 filing to $805M in the plan year 2023 filing.
- The Iron Mountain Companies 401(k) Plan reported participants rose from 7,917 in the plan year 2022 filing to 8,643 in the plan year 2023 filing.
Participants vs Pennsylvania filers
In Pennsylvania, the average filing covers about 822 participants across 5,751 plans. The Iron Mountain Companies 401(k) Plan reports 8,643 participants - 11x that state average ($805M EOY assets).
Pennsylvania filing particulars
| Total Assets (Beginning of Year) | $651M |
|---|---|
| Net Assets (End of Year) | $805M |
| Net Income | $151M |
| Employer EIN | 232588479 |
| Plan Effective Date | 1988-11-09 |
| Filing Status | FILING RECEIVED |
Sponsor Plan History (Iron Mountain Incorporated)
| 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 Pennsylvania
Peer 401(k) plans, same state, same plan type, ranked by total assets.
The Iron Mountain Companies 401(k) Plan vs. nearby 401(k) plans in Pennsylvania, assets vs. participants
- Comcast Corporation Retirement - Investment Plan $17.4B · 93,136
- Cigna 401(k) Plan $13.0B · 66,760
- The Vanguard Retirement and Savings Plan $9.8B · 18,200
- The PNC Financial Services Group, Inc. Incentive Savings Plan $9.3B · 61,697
- The Bank of New York Mellon Corporation 401(k) Savings Plan $9.0B · 25,184
Scale composition for The Iron Mountain Companies 401(k) Plan
The Iron Mountain Companies 401(k) Plan reports $805M in end-of-year assets across 8,643 participants (0.007% of the $12.3T held by all Form 5500 filers in the national rollup , and 0.009% of 93,925,755 covered participants) - about $93,093 per participant (67% of the national average assets-per-participant) . Net income for plan year 2023 was $151M.
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 | Open filing |
| 2023 | 8,643 | $805M | This page |
| 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)
Similar-Sized 401(k) Plans Nationally
401(k) plans in other states closest to The Iron Mountain Companies 401(k) Plan by total assets, not by location.
- Scripps Retirement and Investment Plan (OH) $804M · 5,529
- Thryv Savings Plan (TX) $804M · 2,070
- Entegris, Inc. 401(k) Savings & Profit Sharing Plan (MA) $804M · 3,930
- Dish Network Corporation 401(k) Plan (CO) $806M · 13,820
Frequently Asked Questions
How did The Iron Mountain Companies 401(k) Plan assets move in 2023? ▼
How have Iron Mountain Incorporated plan assets changed over time? ▼
Where does The Iron Mountain Companies 401(k) Plan rank by assets among Form 5500 filers? ▼
Which 401(k) plans are similar in size to The Iron Mountain Companies 401(k) Plan? ▼
Next read for The Iron Mountain Companies 401(k) Plan
Filing takeaways
Ways to act on The Iron Mountain Companies 401(k) Plan's numbers.
- By total assets, The Iron Mountain Companies 401(k) Plan ranks in the top 5% of all filed plans by assets. See the largest plans
- Compare it side-by-side against 3 similar 401(k) plans in Pennsylvania. Compare plans
- Iron Mountain Incorporated's sponsor-wide assets have grown 44.8% since 2022 across 3 plan years on file. More Transportation & Warehousing plans