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Mersen USA Holding Corp.: who to call about your old retirement account

Retirement Savings Plan for the Employees of Mersen USA. BOONTON, NJ. From the plan’s 2025 filing with the U.S. Department of Labor.

Good news: this plan is still running.

It filed for 2025, so if you left money in it, the account should still be there under your name. One phone call usually finds it.

Is this your plan?

From the plan’s public filings. Check that it sounds like the place you worked.

Employer: Mersen USA Holding Corp.Has also filed as Mersen USA Bn Corp., Mersen USA Corp., Carbone-Lorraine North America Corporation
Address on file: 400 Myrtle Ave · Boonton, NJ · 07005
Industry: Manufacturing
Plan: Retirement Savings Plan for the Employees of Mersen USA401(k) plan
When: Start date on the filing: 1992Still running: latest filing is for 2025Has filed since at least 2009
Size: about 1,600 people in the plan, about $180 million in totalabout 390 of them no longer work there and still have money in it. Leaving a balance behind is common.
You may remember: • Had a Roth option

Not the right one? Mersen USA Holding Corp. has 2 other retirement plans:

Retirement Plan for Hourly Employees of Mersen USA · Retirement savings plan · about 770 people · filed 2025
Retirement Plan for Salaried Employees of Mersen USA · Retirement savings plan · about 540 people · filed 2025

Doesn’t sound like it? Search again. Try the company’s legal name, or the name it had when you worked there.

Get this plan’s contact details, free

Tell us where to send them and we’ll email you a link that opens:

✓ The phone number on the plan’s filing
✓ What to say on the call, word for word
✓ The plan ID numbers they will ask you for
✓ The company that likely holds the accounts, with its website and phone number where we have them

If nobody can find you

These official and non-profit registries are free:

DOL Abandoned Plan Search ↗
plans wound down by a custodian after the employer walked away
DOL Retirement Savings Lost & Found ↗
the Department of Labor’s registry of accounts owed to former participants
National Registry of Unclaimed Retirement Benefits ↗
employers and plan administrators list balances they could not deliver
Your state’s unclaimed property office ↗
uncashed distribution checks often end up here

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401kHunter is not affiliated with, endorsed by, or connected to MERSEN USA HOLDING CORP.. Plan figures on this page come from public U.S. Department of Labor Form 5500 filings and reflect the plan’s final reported year. This page is educational and is not investment, tax, or legal advice.