How to Roll Your TSP Into a 401(k) the Right Way

If you're leaving federal service and wondering whether your TSP money can follow you into a new employer's 401(k), the short answer is yes—but only if the new plan accepts incoming rollovers and the money is routed correctly. A direct rollover is usually the safer default because it avoids the mandatory 20% federal withholding that applies when an eligible distribution is paid to you.

Confirm That the New 401(k) Can Accept Your TSP

You generally become eligible to roll TSP funds out after separating from federal service. However, an eligible employer plan is not required to accept a rollover. That decision belongs to the new plan.

Before starting a distribution through TSP, call the new plan's administrator and ask:

• Does this 401(k) accept direct rollovers from the federal Thrift Savings Plan?
• Does it accept both pre-tax and designated Roth rollover money?
• Can it accept tax-exempt contributions, if your uniformed services TSP contains them?
• What payee name, mailing address, account number, and supporting documents should TSP use?
• Are incoming rollover funds subject to different investment, withdrawal, or administrative rules?

TSP's rollover fact sheet is specifically written for plan administrators, trustees, and custodians handling money transferred from TSP.

The fact sheet explains what a receiving plan may need to establish that the payment is an eligible rollover contribution rather than ordinary income. Share it with the administrator if the plan recognizes 401(k) rollovers but seems unfamiliar with TSP.

If the new 401(k) cannot accept one or more portions of your balance, an eligible traditional or Roth IRA may provide another destination. Confirm acceptance and routing instructions with the custodian before requesting the TSP distribution.

Direct Rollover vs. Indirect Rollover

A direct rollover sends the payment to the receiving plan rather than paying it to you. The payment may still travel as a check, but the check is made payable to the receiving plan or custodian for your benefit.

The IRS explains that mandatory 20% federal withholding does not apply when an eligible rollover distribution moves directly to another retirement plan or IRA.

An indirect rollover works differently. The distribution is paid to you, and mandatory 20% withholding generally applies to its taxable portion even when you intend to redeposit the money. You then have 60 days from receipt to roll the eligible distribution into another plan or IRA.

Consider a $50,000 taxable distribution paid to you. With 20% withheld, you receive $40,000. To roll over the full $50,000, you would need to deposit the $40,000 received plus $10,000 from other funds within the 60-day period. If you deposit only $40,000, the withheld $10,000 is generally treated as an amount that was not rolled over. It may be taxable, and an additional early-distribution tax may apply unless an exception covers your situation.

The IRS says a person completing a 60-day rollover must use other funds to replace the withholding if the full original distribution is to remain in retirement accounts.

A direct rollover removes the need to replace that 20% and avoids putting the 60-day deadline on your calendar. Confirm that the receiving plan can process the payment as a direct rollover before initiating it.

Traditional and Roth TSP Money Follow Different Tax Rules

Traditional and Roth TSP balances must retain separate tax accounting during the rollover. They do not always require two destination accounts.

The same receiving 401(k) may accept both portions if it maintains a pre-tax rollover source and a designated Roth source. Ask the administrator to confirm both capabilities and provide separate instructions for each tax source when required.

If the plan accepts only pre-tax money, you may be able to send the traditional portion there and use an eligible Roth IRA or another qualifying destination for the Roth portion. Do not send Roth TSP money to a traditional account.

A January 2020 TSP withdrawal guide illustrates the general pro-rata mechanic with a $150,000 account containing $120,000 of traditional money and $30,000 of Roth money.

In that illustration, an unspecified $10,000 withdrawal consists of $8,000 in traditional money and $2,000 in Roth money. The example helps explain the meaning of pro rata, but the available elections and submission process can change. When the current TSP workflow permits a tax-source election, specify the balance and amount before submitting; otherwise, confirm with TSP how the withdrawal will be allocated.

A direct rollover of traditional TSP money to a pre-tax 401(k) source generally preserves its tax-deferred status. A direct rollover from Roth TSP to a designated Roth account generally preserves Roth treatment, although the receiving plan may need information about contributions, earnings, and the Roth participation period.

Moving traditional TSP money into a Roth account is a conversion rather than a like-for-like rollover. Under the IRS rollover guidance, the pre-tax portion is generally included in taxable income for that year; basis, tax-exempt contributions, and other already-taxed amounts may receive different treatment.

This distinction can matter for uniformed services participants whose accounts include contributions from tax-exempt combat-zone pay. Confirm the destination plan's ability to accept and track those amounts before moving them.

Compare the TSP and 401(k) Before Moving Anything

You are allowed to leave eligible money in TSP after federal service, so there is no need to roll it over simply because you changed employers. The decision usually comes down to costs, investments, account features, and how much you value consolidation.

Use a simple four-part comparison:

1. Total costs: Compare each plan's administrative charges and the expense ratios of the funds you would actually use. Read the new plan's fee disclosure instead of assuming either plan is cheaper.
2. Investment fit: Identify the 401(k) funds that would replace your current TSP allocation. Compare their objectives, risks, benchmarks, and costs rather than relying only on similar fund names.
3. Features you would give up: Money left in TSP retains access to the G Fund. A full rollover removes the transferred balance from TSP and its investment lineup; a partial rollover can preserve a TSP balance and continued access subject to current plan rules.
4. Administrative simplicity: Consolidating retirement savings in one workplace plan can make statements, beneficiary reviews, allocation changes, and rebalancing easier to track. Keeping both accounts may be worthwhile when their features serve different purposes.

TSP tells separated participants that leaving money in an open TSP account remains an option and that taking the entire balance out can close the account unless the participant later returns to TSP-eligible service.

For a concrete comparison, write down the annual administrative fee, expense ratio of each fund you would select, available investment types, and any restrictions on future distributions. Then compare the actual portfolio you would hold in each plan. A long menu of funds adds little value when only two or three meet your needs.

A partial rollover can also create a middle path: consolidate some savings into the new 401(k) while keeping part of the balance in TSP. Ask TSP how the proposed amount would affect the account and available options before committing to it.

Your rollover choice may sit alongside larger decisions about pension eligibility, health coverage, and retirement timing. The federal retirement transition guide can help you review those connected tradeoffs. If separation happened through a reduction in force or another qualifying job loss, the UCFE unemployment guide for federal employees explains the separate unemployment-benefit process.

This guide provides general education, not legal, tax, or financial advice. Confirm the current procedure and account-specific consequences with TSP, the receiving plan administrator, and a qualified tax professional before moving the money.