Forgotten 401(k)s Could Cost Workers $90,000 by Retirement

Article | June 04, 2025

Authored by Johnson & Sheldon, PLLC

Millions of Americans may be unknowingly leaving thousands of dollars on the table by failing to roll over 401(k) accounts when changing jobs, according to new research from online retirement provider PensionBee.

The study estimates there are more than 29 million “left-behind” 401(k) accounts in the U.S., and the missed growth from neglecting them could cost savers up to $90,000 each by retirement.

One of the key concerns involves safe harbor IRAs, which are used by employers to move small 401(k) balances (under $7,000) when workers leave. These accounts are often invested in low-yield options and can be subject to high fees—both of which significantly limit long-term growth.

For example:

• A $4,500 balance in a safe harbor IRA earning just 2% annually (after fees) would grow to about $5,507 over 45 years.
• If rolled into a 401(k) earning 5% annually, that same account could grow to $25,856—a nearly $20,000 difference.

Multiply that over several jobs, and the lost opportunity could exceed the median U.S. retirement savings of $87,000.

PensionBee’s report flagged three key issues with safe harbor IRAs:

1. Overly conservative investments earning less than inflation;
2. Excessive fees that erode account value; and
3. Interest skimming, where providers capture the gap between earned and paid interest as profit.

“These seemingly small defaults can have massive long-term impacts,” said Romi Savova, PensionBee CEO. “Most savers assume their retirement money is growing—but in many cases, it’s not.”

The takeaway? Track down old accounts and consider consolidating them to avoid hidden losses and help ensure a stronger financial future.