What Is the Thrift Savings Plan (TSP)? A Guide for Federal Employees

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The Thrift Savings Plan (TSP) is a defined contribution retirement savings plan for federal civilian employees and members of the uniformed services, including the Ready Reserve. It works much like a private-sector 401(k). Participants contribute part of their pay through payroll deduction, choose how the money is invested, and receive tax advantages. Many participants also receive contributions from their agency or service. The account balance at retirement depends on what goes in and how the chosen investments perform, not on a pension formula.

How the Thrift Savings Plan Works

A TSP account is funded mainly through automatic payroll contributions. Each pay period, the percentage or dollar amount you elect is deducted from your paycheck and deposited in your account, where it is invested according to your fund choices.

Traditional and Roth TSP

Every contribution goes into one of two tax treatments:

• Traditional TSP: contributions come out of pay before income tax is withheld, which lowers your taxable income now. The money and its earnings grow tax-deferred, and withdrawals are taxed as ordinary income in retirement.
• Roth TSP: contributions are made with after-tax pay. Qualified withdrawals in retirement, including earnings, are tax-free.

You can split contributions between the two. Agency contributions have traditionally been deposited on a pre-tax basis regardless of which option you use for your own money.

Contribution limits

The TSP shares the elective deferral limit that applies to 401(k) plans. The IRS sets this limit and adjusts it periodically, so the figure changes from year to year. Participants aged 50 or older can make additional catch-up contributions, and a higher catch-up limit applies to those aged 60, 61, 62 and 63. The deferral limit covers your own traditional and Roth contributions combined; agency contributions do not count against it.

Rollovers in and out

New federal employees can move eligible balances from a previous employer’s 401(k) or from a traditional IRA into the TSP. The reverse is also possible: someone leaving government for a private employer can roll a TSP balance into a 401(k) or an IRA. Rollovers between accounts of the same tax type (pre-tax to pre-tax, Roth to Roth) avoid triggering income tax.

Agency Contributions: The Matching Formula

For FERS employees and BRS members, the government’s contribution has three layers:

1. Automatic 1%: the agency deposits 1% of basic pay every pay period, even if you contribute nothing.
2. Dollar-for-dollar match on the first 3% of pay you contribute.
3. 50 cents per dollar on the next 2% of pay you contribute.

Contributing 5% of pay therefore brings the full 5% from the government. Contributing more than 5% is allowed up to the annual limit, but it earns no additional match. Employees still covered by the older Civil Service Retirement System (CSRS) can contribute to the TSP but do not receive agency contributions.

Worked example (hypothetical)

Assume a FERS employee earns $70,000 in basic pay, and ignore pay raises and investment returns.

Moving from 3% to 5% costs this employee $1,400 more a year in contributions but adds $700 in agency money, an immediate 50% return on that extra slice before any market gains. Going from 0% to 5% turns $700 a year into $7,000, a gap that widens over decades through compound interest.

Vesting

Your own contributions and their earnings always belong to you. Matching contributions vest immediately. The automatic 1% contribution and its earnings are subject to a service requirement (generally three years, or two years for certain positions). If you leave before meeting it, the government can take back those amounts.

TSP Investment Options

The TSP keeps its menu short:

• G Fund (Government Securities Investment Fund): invested in special-issue U.S. Treasury securities available only to the TSP. It pays a government-set interest rate and is designed not to lose principal.
• F Fund (Fixed Income Index Investment Fund): tracks a broad U.S. investment-grade bond index.
• C Fund (Common Stock Index Investment Fund): tracks the S&P 500, the index of 500 large and mid-sized U.S. companies.
• S Fund (Small Capitalization Stock Index Investment Fund): tracks U.S. stocks outside the S&P 500, mostly small and mid-sized companies.
• I Fund (International Stock Index Investment Fund): tracks stocks of companies in developed and emerging markets outside the U.S.
• L Funds (Lifecycle Funds): target-date portfolios built from the five individual funds. Each is tied to a year when you expect to need the money, and its mix shifts from stocks toward the G and F funds as that date approaches. L Income is for those already drawing on their savings.
• Mutual fund window: access to a broader lineup of outside mutual funds. You need at least $40,000 in your TSP account to use it, and no more than 25% of your total balance can be invested through the window. Its funds carry their own expenses and additional window fees.

The F, C, S and I funds are index funds. Their investment management is contracted out, currently to BlackRock Institutional Trust Company, under oversight from the FRTIB. The FRTIB, not a private company, is the plan administrator and is legally bound to manage the TSP prudently and in the interest of participants and their beneficiaries.

Fees

TSP fees are expense ratios that come out of fund returns rather than out of separate bills. They have historically been very low, around 0.05% for the core funds. On a hypothetical $100,000 balance, that is about $50 a year.

Loans and Withdrawals

TSP loans

While still employed by the government, you can borrow from your own contributions and their earnings, up to $50,000. The loan is repaid through payroll deductions with interest, and the interest goes back into your account.

Withdrawals in retirement

After separating from service, you can leave the money invested, withdraw it, or combine methods. Installment payments can be set monthly, quarterly or annually, either as a fixed dollar amount you choose or as an amount based on your life expectancy and balance, recalculated each year. Single withdrawals and purchasing an annuity through the plan are also options.

Withdrawals before age 59½ normally carry a 10% early withdrawal penalty on the taxable portion. The TSP follows the “rule of 55”: if you separate from federal service in or after the year you turn 55, withdrawals from the TSP are free of that penalty. For employees covered by FERS special provisions (such as law enforcement officers, firefighters and air traffic controllers), the age drops to 50.

Required minimum distributions (RMDs) begin at age 73 for traditional balances. Roth TSP balances are no longer subject to RMDs while the participant is alive, following changes enacted in 2022 that took effect in 2024.

What Happens to Your TSP If You Leave Federal Service

If you quit with a balance of $200 or more, the account stays open and invested. You can still change fund allocations but cannot make new contributions, and any unvested automatic 1% contributions and their earnings are removed. If you later return to federal service, you can resume contributing to the same account.

TSP vs. 401(k), IRA and Pensions

Is the TSP a 401(k)?

Not technically, but it is built on the same model: an employer-sponsored defined contribution plan with the same deferral limits, pre-tax and Roth options, loans and the age 55 separation rule. The TSP is what the federal government offers in place of a 401(k). The practical differences are its narrower fund menu and low fees.

TSP vs. IRA

You can hold a TSP and an IRA at the same time; it is not a choice between them. Key differences:

• Contributions: the TSP’s annual limit and catch-up limits are well above the IRA limit, so it can absorb far more savings each year.
• Employer money: an IRA you open yourself receives no employer contributions (SEP and SIMPLE IRAs are exceptions tied to an employer). The TSP can add up to 5% of pay.
• Investment choice: an IRA at a brokerage can hold individual stocks, bonds, ETFs and thousands of funds. The TSP is limited to its own funds plus the restricted mutual fund window.
• Fees: TSP core fund fees are low; IRA costs depend entirely on what you buy and where.
• Flexibility: IRA withdrawals after 59½ can be taken in any amount at any time, and IRAs have no loan feature. The TSP offers loans and the age 55 rule, but within its defined withdrawal methods.

Is the TSP a defined benefit plan?

No. A defined benefit plan promises a set payment based on salary and years of service. The TSP promises nothing beyond what your account holds. For FERS employees, the defined benefit piece is the separate FERS basic annuity; the TSP and Social Security are the other two parts of the three-part federal retirement system. That is why the TSP carries more weight for FERS and BRS participants than it did for CSRS employees, whose pension was designed to cover more of their retirement income.

Accessing Your TSP Account

Accounts are managed online at tsp.gov through My Account, where you can view balances, change fund allocations, start loans and request withdrawals. Contribution amounts are changed through your agency’s payroll or personnel system, not through tsp.gov. The ThriftLine is 877-968-3778 (404-233-4400 from outside the U.S.), and logged-in users can send secure messages through the Message Center.

Limitations of the Thrift Savings Plan

• Narrow menu: the core options are index funds. Anything else goes through the mutual fund window, with its balance minimum, 25% cap and extra fees.
• Market risk: every fund except the G Fund can lose value. The G Fund protects principal but its returns may not keep pace with inflation over long periods.
• Rigid withdrawals: money must come out through the plan’s set methods.
• Vesting and match ceiling: short-tenure employees can lose the automatic 1%, and contributions above 5% of pay earn no extra government money.

FAQs

The Bottom Line

Federal employees and service members covered by FERS or BRS rely on the TSP as one of three parts of their retirement income. Contributing at least 5% of pay captures the full government match, which adds money no other choice can replace. The fund menu is narrow, but low fees and high contribution limits make the TSP a strong core account that can sit alongside an IRA.