401(k) Rollover to an IRA: How to Avoid the Cash Drag Trap

When Marcus left his job at a logistics company outside Dallas in March 2023, he did the responsible thing. He rolled his $112,000 401(k) into an IRA at a big brokerage, filled out the forms, watched the balance show up a few weeks later, and crossed it off his list. Then he stopped thinking about it.

He logged in again this past February, almost three years later, to update his address. The $112,000 was still sitting in a money market fund. It had never been invested in anything else. He had moved his retirement savings to a brand-new account and then, without realizing it, parked the whole thing in the financial equivalent of a savings jar.

Marcus is not careless. He's in good company, and the company is enormous. A 401(k)-to-IRA rollover is one of the most common money moves Americans make, and it hides two separate traps that catch people at opposite ends of the process. The first is choosing the wrong destination for the money. The second is forgetting to actually invest it once it lands. Most rollover advice covers the first trap and ignores the second, which is backwards, because the second one is where people quietly lose the most.

The part most people get right: where the money goes

When you leave a job, your old 401(k) doesn't have to move. You generally have four options, and the right one depends on your situation more than on which brochure landed in your inbox.

Leave it in the old plan

If your balance is above $7,000, you can usually keep it right where it is. That's not always lazy. Some employer plans have access to institutional funds with rock-bottom expense ratios you can't buy as an individual, and a 401(k) carries strong federal creditor protection. The downside is that left-behind accounts get forgotten. The retirement platform Capitalize estimated there were 29.2 million forgotten 401(k) accounts holding about $1.65 trillion as of May 2023. An account you never look at is an account nobody is managing.

Move it into your new employer's 401(k)

If your new job offers a decent plan, rolling the old balance into it keeps everything in one place and preserves that 401(k) creditor protection. It also keeps the door open for the backdoor Roth strategy, which I'll come back to, because a traditional IRA balance can quietly sabotage it.

Roll it into an IRA

This is the most popular path, and for good reason. An IRA usually gives you far more investment choices than a 401(k)'s curated menu, often at lower cost, and it consolidates old accounts into something you control. Rollovers are now the dominant force in the IRA market. The Investment Company Institute reported that IRAs held $19.2 trillion at the end of 2025, roughly 39% of all U.S. retirement assets, and the research firm LIMRA pegged retail rollover activity at about $855 billion in 2025 alone. This is where most of the money goes. It's also where the second trap lives.

Cash it out

Please don't, unless you truly have no other option. If you're under 59½, cashing out a traditional 401(k) means income tax on the whole balance plus a 10% early-withdrawal penalty. On Marcus's $112,000, that could vaporize $30,000 or more before he saw a dime, and the retirement savings would be gone for good. There are better ways to handle a cash crunch than torching your future.

Direct vs. indirect: the 20% trap

Once you've decided on an IRA, how you move the money matters as much as where it goes.

A direct rollover, sometimes called a trustee-to-trustee transfer, sends the money straight from your old plan to your new IRA. You never touch it. This is the clean way, and it's the way you want.

An indirect rollover hands you a check, and you have 60 days to deposit it into the new account yourself. The catch is brutal and most people don't see it coming: when a 401(k) plan cuts you a check directly, the IRS requires it to withhold 20% for taxes. On Marcus's balance, that's $22,400 the plan would send to the IRS instead of to him. To complete a full rollover, he'd have to come up with that $22,400 out of his own pocket to deposit alongside the check, then wait until he files his taxes to get it back. Miss the 60-day window and the whole thing becomes a taxable distribution, penalty included.

So the rule is simple. Always ask for a direct rollover. If anyone hands you a check made out to you personally, something went wrong.

What the rollover brochure won't tell you

A few details rarely make it into the glossy "roll over today" pitch, and any one of them can change your decision.

The Rule of 55 lets you take penalty-free withdrawals from a 401(k) if you leave your job in or after the year you turn 55. Roll that 401(k) into an IRA and you lose that early-access bridge, because IRAs don't offer it until 59½. If there's any chance you'll retire early and need that money, think twice before moving it.

Creditor protection isn't equal either. Money in a 401(k) gets near-bulletproof protection under federal law. IRAs are protected too, but the rules vary by state and the bankruptcy shield is capped, recently north of $1.5 million. For most people this is academic. For someone in a high-liability profession, it's worth a conversation with an advisor.

Then there's the backdoor Roth wrinkle. If you earn too much to contribute to a Roth IRA directly and use the backdoor method, a pre-tax traditional IRA balance triggers the pro-rata rule and can make those conversions a taxable mess. Rolling a 401(k) into a traditional IRA can accidentally close that door. If you use the backdoor Roth, rolling into your new employer's 401(k) instead often keeps it open.

One more thing if your balance is small. Under the SECURE 2.0 Act, employers can force out former employees' accounts of $7,000 or less, up from the old $5,000 limit, effective January 1, 2024. If your old balance is under that line, the plan may eventually move it for you into a default IRA whether you act or not. Better to decide on purpose than to let a force-out land your money somewhere random.

The trap on the other side: your money probably isn't invested

Here's the part nobody warns you about. When your rollover lands in a new IRA, the cash does not invest itself.

This is the single most expensive misunderstanding in the whole process. A 401(k) usually drops your contributions straight into a target-date fund by default, so the money is working from day one. An IRA doesn't work that way. The cash arrives in a settlement or money market fund and sits there, earning a modest yield, until you place a trade. If you don't know that, you assume you're invested. You are not.

The scale of this is staggering. Vanguard studied investors who rolled money into its IRAs and found that 28% of them were still sitting entirely in cash a full year later. Worse, the cash tends to stick: roughly 30% of rollover investors leave the money in cash for about seven years, according to research highlighted by 24/7 Wall St. in June 2026. Vanguard's behavioral team estimated that Americans forgo about $172 billion in investment gains every year because of idle IRA cash. "IRA cash is a billion-dollar blind spot," said Andy Reed, Vanguard's head of investor behavior research.

What makes it tragic is that it's almost never a choice. When Vanguard surveyed the people who'd stayed in cash, two-thirds didn't even know how their IRA was allocated. Close to half believed their contributions had been invested automatically. These weren't naive investors either. Most owned other investment accounts and understood the basics. They simply assumed an IRA behaved like a 401(k), and it doesn't.

Now the math, because it's the whole point. Say you roll over $112,000, like Marcus, and leave it in a money market fund yielding 3.6%, roughly where Vanguard's federal money fund sat in early June 2026. Let it ride for 20 years and it grows to about $227,000. Invest that same $112,000 in a diversified portfolio earning a long-run 7% instead, and it grows to about $433,000. The gap is just over $206,000, and the only difference is whether you placed a single trade after the money arrived. Vanguard's own estimate for a younger investor is similar in spirit: someone under 55 who moves rollover cash into a target-date fund rather than leaving it idle could end up with at least $130,000 more by age 65.

Money markets aren't bad places for cash you need next year. They're a terrible place to accidentally store your entire retirement for two decades.

The Bottom Line

A rollover isn't done when the balance shows up. It's done when the money is actually invested. Three things to do this week:

1. Log into every old retirement account and check the holdings, not just the balance. If you've done a rollover in the past few years, look at what the money is actually in. If it says "money market," "settlement fund," or "cash," your retirement savings are sitting on the bench. This takes five minutes and is the highest-value check on this list.

2. If you're planning a rollover now, ask for a direct trustee-to-trustee transfer. Never accept a check made out to you personally. It triggers a 20% withholding and a 60-day clock you don't want. And before you move a 401(k) to an IRA, confirm it won't cost you the Rule of 55 or break a backdoor Roth strategy you rely on.

3. Once the cash lands, place the trade the same day. Pick a low-cost target-date fund matched to your retirement year, or a simple index fund, and buy it. Set a calendar reminder for one week later to confirm the order filled. Idle cash doesn't announce itself, so you have to go looking.