Do you have any lost or forgotten 401(k)s?

How many lost and forgotten 401(k)s are out there?

A lot, and the number keeps growing. As of July 2025, an estimated 31.9 million 401(k) accounts have been left behind or forgotten, holding roughly $2.13 trillion in assets, according to research by Capitalize and the Center for Retirement Research at Boston College. That's nearly a quarter of all the money held in 401(k) plans nationwide.

The problem is accelerating. The number of forgotten accounts has almost doubled over the past decade, and the assets inside them have grown nearly 30% in just two years. An estimated 3.5 million accounts were left behind in 2023, 4 million in 2024, and a projected 4.2 million in 2025. The average forgotten account isn't trivial either, at about $66,691.

How does a 401(k) become lost or forgotten?

Usually due to job changes. Workers born between 1957 and 1964 held an average of more than 12 jobs before age 54, according to the Bureau of Labor Statistics, and each job may have come with its own 401(k). When you leave, the account doesn't follow you. It stays with your former employer's plan administrator unless you actively roll it over.

In the rush of starting a new job, rolling over an old 401(k) is easy to put off and easy to forget entirely. Over years and several job changes, accounts pile up at different providers, statements get sent to old addresses, and plans occasionally change administrators. Eventually you may not remember where an account is held, or that it exists at all.

Forgotten doesn't mean harmless. After you leave, your old company often stops covering the plan's administrative fees, leaving you to pay them. Combined with money that may be sitting in a low-return default investment, Capitalize estimates that a single neglected account could cost an individual more than $500,000 in foregone retirement savings over a career.

How often do people change jobs?

Job-switching is what scatters retirement savings, and it happens throughout a career, not just at the start. People born between 1957 and 1964 held an average of 12.7 jobs between ages 18 and 56. The pace is highest early on, but it never stops: even between ages 45 and 56, the average worker still changed jobs more than twice. Each of those moves is a moment when a 401(k) can be left behind.

How do I find my lost and forgotten 401(k)s?

Tracking down an old account is often more straightforward than people expect. A few places to start:

• Search the Retirement Savings Lost and Found, a database launched by the U.S. Department of Labor in late 2024 specifically to help workers locate old workplace plans.
• Search the National Registry of Unclaimed Retirement Benefits to see if a former employer has flagged an account under your name.
• Check your state's unclaimed property database, since funds from closed accounts are sometimes turned over to the state.
• Contact a former employer's HR department directly and ask for details of the 401(k) you contributed to.
• Dig up old account statements or W-2s, which list the plan provider and can give you an account number to call about.

Have your Social Security number, the approximate dates you worked at each employer, and any old plan paperwork on hand. It will make every one of these searches faster.

What should I do once I find an old 401(k)?

Finding the account is only the first step. Once you've located it, you generally have the same options as anyone changing jobs: leave it where it is, roll it into your current employer's 401(k), or roll it into an IRA. Each has trade-offs around fees, investment choices, and convenience.

Consolidating scattered accounts is what most people ultimately do, and the data shows why. As households approach retirement, money steadily migrates out of employer 401(k)s and into IRAs. If you'd like to weigh your choices, our guide to 401(k) rollovers walks through each option in plain English.

How can Nanotoa help?

Most people don't end their careers with a single retirement account. The average worker born between 1957 and 1964 held more than 12 jobs before age 54, and each one may have come with its own 401(k). It's no surprise that an estimated 29 million 401(k) accounts have been left behind or forgotten, holding well over $1 trillion in assets. When your money is scattered across old employers, brokers, and IRAs, it's hard to know what you actually have.

Nanotoa fixes that. We automatically pull all of your accounts: 401(k)s, IRAs, brokerage, savings, even your home and mortgage, into a single asset and liability ledger. Instead of logging into five different sites, you see your entire financial picture in one place.

Then we put that picture to work. Nanotoa projects what your income could look like if you retire at 62, 65, or 67, so you can see the trade-offs of each choice before you make them. That matters, because most people are flying blind. In one survey, 70% of women and 56% of men agreed it's difficult to know how their savings will translate into monthly retirement income.

Whether you're deciding what to do with an old 401(k) or just trying to understand if you're on track, Nanotoa turns a pile of disconnected accounts into one clear answer: here's what you have, and here's what it means for retirement.