Iron Mountain Incorporated 401(k) Plan: Login, Facts & Contact Information

Iron Mountain Incorporated 401(k) Plan Facts

Plan name
THE IRON MOUNTAIN COMPANIES 401(K) PLAN
Plan type
401(k) with employer contributions and profit sharing
Plan sponsor
IRON MOUNTAIN INCORPORATED
Participants
12,353 (10,113 active employees)
Former employees with a balance
3,037
Plan assets
$943,119,140 at Dec 31, 2024
Average account balance
$73,526 across 12,827 accounts
Employer contributions
$27,744,204 in plan year 2024 (27% of all contributions)
Recordkeeper
Fidelity Investments Institutional
Plan year
Jan 1, 2024 – Dec 31, 2024
Plan established
Nov 9, 1988
✓ Employer contributions✓ Automatic enrollment✓ Default investment for undecided participants✓ Participants choose their own investments✓ Self-directed brokerage window✓ Profit sharing— Company stock (ESOP)

Source: Form 5500 for plan year 2024 (Jan 1, 2024 – Dec 31, 2024), filed Oct 10, 2025. Public filing with the U.S. Department of Labor.

Money in and out in plan year 2024

  • $102.9 million went into the plan in contributions, $27.7 million of it from the employer (27%).
  • $93.4 million was paid out to participants.
  • Investment and other income added $130.1 million.
  • Administrative expenses were $922,129, about $72 per account.

How the Iron Mountain Incorporated 401(k) changed, 2019–2024

Plan yearParticipantsPlan assetsEmployer contributionsBenefits paid
201913,216$652.6 million$13.0 million$52.7 million
202012,836$713.2 million$13.3 million$91.2 million
202112,737$809.5 million$14.1 million$74.6 million
202212,473$651.3 million$15.9 million$95.9 million
202311,808$804.6 million$18.6 million$61.5 million
202412,353$943.1 million$27.7 million$93.4 million

Iron Mountain Incorporated 401(k) Contact Information

Phone
855-462-7547
Mailing address
1101 ENTERPRISE DRIVE, ROYERSFORD PA 19468
Plan sponsor
IRON MOUNTAIN INCORPORATED
Employer identification number (EIN)
23-2588479
Plan number
001

Questions about the Iron Mountain Incorporated 401(k)

Does Iron Mountain Incorporated contribute to the 401(k)?

Yes. The plan reports an employer contribution arrangement. In plan year 2024 the employer contributed $27.7 million, 27% of all contributions.

Does the Iron Mountain Incorporated 401(k) have automatic enrollment?

Yes. The plan reports automatic enrollment of eligible employees.

How many people are in the Iron Mountain Incorporated 401(k) plan?

12,353 participants at the start of plan year 2024, 10,113 of them active employees, and 3,037 former employees who still had money in the plan.

What is the average 401(k) balance at Iron Mountain Incorporated?

About $73,526 per account: $943.1 million in plan assets across 12,827 accounts with a balance at the end of plan year 2024.

Who manages the Iron Mountain Incorporated 401(k) accounts?

Fidelity NetBenefits (listed on the filing as FIDELITY INVESTMENTS INSTITUTIONAL) is the plan's recordkeeper, which is where participants log in to see their balance.

I no longer work at Iron Mountain Incorporated. How do I access my 401(k)?

Your account stays with Fidelity NetBenefits after you leave, so you can log in with the same credentials. If your balance was small, the plan may have rolled it into an IRA in your name. If you can't find it, Beagle can locate it for you.

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