401(k) · DOL Form 5500 · 2023

Iron Mountain Incorporated 401(k) Plan

Data updated 2026-08-25

$805M
Total assets Above avg plan size
8,643
Participants Very large workforce
98th
Percentile by assets National rank
$93,093
Avg per participant Below avg balance/head
PlainRetire home → About this data RSS: change history

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.

  • #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.

#3,272
in Transportation & Warehousing (3,362 peers)
+23.5%
assets growth YoY
8.1×
vs typical plan assets (national mean)

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 2023 · DOL Form 5500

$804,601,580 Top 2% higher than 98% of 127,068 filed plans

This plan $0 $2,050,000,000 every filed plan with reported assets, bucketed by value

Dashed line + filled bar = this entry, among filed plans.

Source U.S. Department of Labor Form 5500 filings (EBSA) · plan year 2023

The Iron Mountain Companies 401(k) Plan's large-plan peer group by participant headcount

Plan-year 2023 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 (8,643 participants).

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.

See the national 2022→2023 release diff →

EBSA filing schedule strip

Filing strip 232588479 · Iron Mountain Incorporated PY 2023 · 401(k)

The Iron Mountain Companies 401(k) Plan · $805M · 8,643 · 98th

  • EIN $805M
  • EIN 8,643
  • EIN 98th
  • EIN 401(k)
  • EIN near Scripps Retirement and Investment Plan
  • EIN ind #3272

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 Pennsylvania →

The Iron Mountain Companies 401(k) Plan in the asset neighbourhood

Dish Network Corporation 401(k) PlanDish Network Corporation 401…$806MThe Iron Mountain Companies 401(k) PlanThe Iron Mountain Companies …$805MScripps Retirement and Investment PlanScripps Retirement and Inves…$804MThryv Savings Plan$804MEntegris, Inc. 401(k) Savings & Profit Sharing PlanEntegris, Inc. 401(k) Saving…$804M
End-of-year total assets ($M) among The Iron Mountain Companies 401(k) Plan and nearest nationwide 401(k) peers. Source: DOL Form 5500 plan year 2023.

Pennsylvania filing particulars

Total Assets (Beginning of Year)$651M
Net Assets (End of Year)$805M
Net Income$151M
Employer EIN232588479
Plan Effective Date1988-11-09
Filing StatusFILING 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
$600M$700M$800M$900M$1,000M 202220232024 $651M $943M ▲ +44.8%
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 Scatter plot of 6 data points. 020000400006000080000100000 -505101520 Total assets ($B) Participants The Iron Mountain Companies 401(k) Plan, Total assets ($B): 0.80460158 · Participants: 8643The Iron Mountain Companies 401(k) PlanComcast Corporation Retirement - Investment Plan, Total assets ($B): 17.368669862 · Participants: 93136Comcast Corporation Retirement - Investment PlanCigna 401(k) Plan, Total assets ($B): 13.003870935 · Participants: 66760Cigna 401(k) PlanThe Vanguard Retirement and Savings Plan, Total assets ($B): 9.765617477 · Participants: 18200The Vanguard Retirement and Savings PlanThe PNC Financial Services Group, Inc. Incentive Savings Plan, Total assets ($B): 9.339762 · Participants: 61697The PNC Financial Services Group, Inc. Incentive Savings PlanThe Bank of New York Mellon Corporation 401(k) Savings Plan, Total assets ($B): 8.955655142 · Participants: 25184The Bank of New York Mellon Corporation 401(k) Savings Plan
The Iron Mountain Companies 401(k) Plan vs. nearby 401(k) plans in Pennsylvania, assets vs. participants
Compare The Iron Mountain Companies 401(k) Plan side-by-side with 3 peers →

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's out-of-state 401(k) peers by assets and headcount

Outside Pennsylvania, the nearest 401(k) by assets is Scripps Retirement and Investment Plan in OH ($804M); by covered participants it is Deaconess Health System, Inc. 401(k) Plan in IN (8,651 participants). Same-state nearby plans are listed separately above.

Closest by plan assets

Nearest other-state filings by tot_assets_eoy ($805M here).

Similar participant headcount

Nearest other-state filings by covered participants (8,643 participants); asset peers above are excluded.

DOL Form 5500 plan year 2023. Asset totals can differ widely at the same headcount; neither axis is a quality rating.

Frequently Asked Questions

How did The Iron Mountain Companies 401(k) Plan assets move in 2023? ▼
The Iron Mountain Companies 401(k) Plan grew sharply - up 23.5% during 2023, from $651M to $805M. Reported net income was $151M.
How have Iron Mountain Incorporated plan assets changed over time? ▼
Across 3 plan years on file (2022-2024), Iron Mountain Incorporated's sponsor-wide assets grew 44.8%, from $651M to $943M.
Where does The Iron Mountain Companies 401(k) Plan rank by assets among Form 5500 filers? ▼
The Iron Mountain Companies 401(k) Plan ranks in the 98th percentile by end-of-year assets among 127,072 plans that reported assets for plan year 2023 (in the top 5% of all filed plans by assets).
Which 401(k) plans are similar in size to The Iron Mountain Companies 401(k) Plan? ▼
Among 401(k) plans in other states, the closest by assets is Scripps Retirement and Investment Plan in OH ($804M, 5,529 participants).
Which 401(k) plans cover a similar participant headcount to The Iron Mountain Companies 401(k) Plan? ▼
Among 401(k) plans in other states, the closest by covered participants is Deaconess Health System, Inc. 401(k) Plan in IN (8,651 participants, $738M in assets).

Source: U.S. Department of Labor, Employee Benefits Security Administration (EBSA), Form 5500 public disclosure dataset. Plan year 2023.

Source: DOL EFAST2 filing system (efast.dol.gov) - original filing retrieval by EIN 232588479.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from U.S. Department of Labor Form 5500 filings (EBSA). See our methodology for details.