What is a Thrift Savings Plan? The Thrift Savings Plan (TSP) is a retirement savings and investment plan for federal government employees and members of the uniformed services, including the Ready Reserve, and it is the federal equivalent of a private-sector 401(k). It is a defined contribution plan, meaning your future retirement income depends on how much is contributed and how those contributions grow, not on a guaranteed pension formula (Source: TSP.gov, About the TSP, 2026).
The TSP is the federal government’s defined contribution retirement plan for federal employees and uniformed-service members. Participants contribute through payroll deduction into low-cost investment funds, and eligible FERS employees receive agency contributions. For 2026 the elective deferral limit is $24,500 (Source: IRS Notice 2025-67, via IRS newsroom, 2025).
What is a Thrift Savings Plan, and how does it work?
A Thrift Savings Plan is the federal government’s defined contribution retirement plan, established by the Federal Employees’ Retirement System Act of 1986 and administered by the Federal Retirement Thrift Investment Board (FRTIB) (Source: TSP.gov, About the TSP, 2026). Participants contribute a portion of pay through payroll deduction, choose from a small menu of investment funds, and the account balance grows with contributions plus earnings.
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Because it is a defined contribution plan, the eventual payout is not a fixed, guaranteed amount. Retirement income depends on total contributions made during working years, any agency or service contributions, and accumulated investment earnings (Source: TSP.gov, About the TSP, 2026).
The TSP is frequently described as the world’s largest defined contribution plan. Public FRTIB reporting has placed participation at roughly 7 million-plus accounts and assets near the $900 billion range as of the end of 2024. These scale figures shift over time, so current totals may differ.
Where the TSP fits in the federal retirement package
For employees under the Federal Employees’ Retirement System (FERS), the TSP is one of three parts of retirement income, alongside the FERS basic annuity (pension) and Social Security (Source: TSP.gov, About the TSP, 2026). The TSP is the portion the participant funds and directs, while the FERS annuity and Social Security are separate systems.
How the three pieces interact in retirement, including how withdrawals may affect taxes, can be involved. For related tax mechanics, see the Q3 Advisors research on the Social Security tax torpedo and Medicare IRMAA 2026 brackets.
Who is eligible for a Thrift Savings Plan?
Eligibility for the TSP is limited to federal government civilian employees and members of the uniformed services, including the Ready Reserve (Source: TSP.gov, About the TSP, 2026). Most FERS civilian employees and members covered under the Blended Retirement System participate. Private-sector civilians cannot open a TSP; the closest equivalents outside government are employer 401(k) plans and individual retirement accounts (IRAs).
Newer federal hires are generally enrolled automatically. FERS employees hired after October 1, 2020 are typically auto-enrolled at a 5% contribution rate, and uniformed-service members under the Blended Retirement System are commonly enrolled in the 3% to 5% range. Participants can change or stop contributions at any time, subject to plan rules.
Traditional vs. Roth TSP: the tax choice
The TSP offers two contribution tax treatments: traditional (pre-tax) and Roth (after-tax), and participants can use both at the same time (Source: TSP.gov, Contribution Types, 2026). Traditional contributions reduce current taxable income and are taxed on withdrawal, while Roth contributions are made with after-tax dollars and qualified withdrawals may be tax-free.
A detail many participants do not expect: any agency or service matching and automatic contributions always go into the traditional (pre-tax) balance, even for someone who contributes only to Roth (Source: TSP.gov, Contribution Types, 2026). That creates a taxable bucket alongside a Roth bucket, which can matter for later tax planning.
| Feature | Traditional TSP | Roth TSP |
|---|---|---|
| Contribution tax treatment | Pre-tax (reduces current taxable income) | After-tax |
| Withdrawal tax treatment | Taxed as ordinary income | Qualified withdrawals may be tax-free |
| Agency/service match lands in | Traditional balance | Traditional balance (not Roth) |
| Lifetime RMDs | Apply (see RMD section) | Not required for years after 2023 |
As of January 28, 2026, the TSP added a Roth in-plan conversion feature, letting participants convert traditional balances to Roth through My Account without first rolling the money to an IRA (Source: TSP.gov, Contribution Types, 2026). Deciding whether a conversion fits an individual situation involves tax analysis; Q3 Advisors covers this in its Roth conversion service and in the guide on TSP Roth conversion for federal employees.
How much does the government match in the TSP?
Under FERS, an eligible participant who contributes 5% of basic pay receives a total agency or service contribution of 5%: a 1% automatic contribution plus a 4% match (Source: TSP.gov, Contribution Types, 2026). The automatic 1% is paid each pay period regardless of whether the employee contributes.
The match structure works per pay period on the first 5% the employee contributes: the first 3% is matched dollar-for-dollar, and the next 2% is matched 50 cents on the dollar (Source: TSP.gov, Contribution Types, 2026). The automatic 1% continues even if the employee stops contributing, but matching stops when employee contributions stop.
| Your contribution | Agency automatic | Agency match | Total added by agency |
|---|---|---|---|
| 0% | 1% | 0% | 1% |
| 3% | 1% | 3% | 4% |
| 5% | 1% | 4% | 5% |
Employees under the older Civil Service Retirement System (CSRS) may contribute to the TSP but do not receive agency matching or the automatic 1% (Source: TSP.gov, Contribution Types, 2026).
The TSP investment funds
The TSP offers five core individual funds plus a series of Lifecycle (L) target-date funds (Source: TSP.gov, Investment Options, 2026). The individual funds cover government securities, bonds, and domestic and international stocks, and each L Fund blends the five into a mix that adjusts over time.
| Fund | What it holds |
|---|---|
| G Fund | U.S. Treasury securities specially issued to the TSP; principal and interest guaranteed by the U.S. government |
| F Fund | Fixed income index tracking the Bloomberg U.S. Aggregate Bond Index |
| C Fund | Common stock index tracking large U.S. companies (S&P 500) |
| S Fund | Small capitalization U.S. stock index (completion index) |
| I Fund | International stock index |
The Lifecycle (L) Funds are target-date options that automatically shift from a higher stock allocation toward more conservative holdings as a target retirement year approaches (Source: TSP.gov, Lifecycle Funds, 2026). As of 2026 there are eleven L Funds, including L 2065 and the newer L 2070 (inception July 26, 2024) (Source: TSP.gov, Lifecycle Funds, 2026).
A mutual fund window is also available for participants who want access to outside mutual funds. It carries extra fees and generally caps the amount that can be invested through it at 25% of a participant’s total TSP balance.
Low costs as a signature feature
Low administrative expenses are a defining trait of the TSP. The plan reported a net administrative expense ratio of 0.042% (4.2 basis points) for 2019, and the L 2070 Fund shows a net administrative expense ratio of 0.033%, or about $0.33 per $1,000 of balance (Source: TSP.gov, Expenses and Fees, 2026). Current per-fund figures may differ, and the live table on tsp.gov shows the latest year.
What are the TSP contribution limits for 2026?
For 2026, the TSP elective deferral limit is $24,500, up from $23,500 in 2025 (Source: IRS Notice 2025-67, via IRS newsroom, 2025). The TSP shares this limit with 401(k), 403(b), and governmental 457 plans because the IRS applies the same Internal Revenue Code section 402(g) cap to all of them (Source: IRS newsroom, 2025).
| 2026 limit | Amount | Applies to |
|---|---|---|
| Elective deferral (402(g)) | $24,500 | Regular employee contributions |
| Age-50 catch-up (414(v)) | $8,000 | Participants age 50 and older |
| Super catch-up (ages 60-63) | $11,250 | Participants ages 60, 61, 62, 63 |
| Annual additions (415(c)) | $72,000 | Total contributions incl. agency match |
The age-50 catch-up is $8,000 for 2026, and a higher SECURE 2.0 catch-up of $11,250 applies to participants who are ages 60, 61, 62, or 63 (Source: IRS Notice 2025-67, via IRS newsroom, 2025). The section 415(c) annual additions limit, which caps total contributions including agency contributions, is $72,000 for 2026 (Source: IRS COLA table, 2025). For a broader breakdown, see the Q3 Advisors 2026 retirement contribution limits guide.
A SECURE 2.0 rule also affects who can make catch-up contributions on a pre-tax basis. Participants whose prior-year FICA wages exceeded $150,000 are generally required to make catch-up contributions on a Roth (after-tax) basis rather than traditional. The exact implementation continues to phase in, and specifics may depend on individual circumstances.
When can I withdraw from my TSP without penalty?
Withdrawals from a traditional TSP are generally taxed as ordinary income, and an additional 10% early-withdrawal penalty can apply before age 59.5 (Source: IRS, Retirement Topics, 2025). In-service withdrawals are generally available starting at age 59.5, and separating from federal service in or after the year you turn 55 (age 50 for certain special categories such as many public-safety roles) can allow penalty-free access earlier.
The TSP also permits loans and hardship withdrawals under specific conditions. Loans come in general-purpose and residential types, and hardship withdrawals require a qualifying financial need. Each option has its own rules, tax effects, and potential long-term impact on the account balance.
What happens to my TSP when I leave federal service?
After separating from federal service, a participant can generally keep the TSP account if the vested balance is $200 or more, leaving the money invested in TSP funds (Source: TSP.gov, 2026). Alternatively, the balance can often be rolled over into an IRA or another eligible employer plan, or left in place while withdrawal options are considered.
Matching contributions are vested immediately, while the FERS automatic 1% contribution generally vests after two to three years of service, depending on position. Rolling a TSP into an IRA or comparing it to a 401(k) involves tradeoffs in cost, investment choice, and creditor protections that can vary by situation.
At what age are TSP required minimum distributions required?
Required minimum distributions (RMDs) from a traditional TSP generally begin at age 73 for participants who reach age 72 after December 31, 2022, under the SECURE 2.0 Act (Source: IRS Publication 590-B, 2025). The first RMD is due by April 1 of the year after you turn 73, and later RMDs are due by December 31 each year.
Roth TSP balances are treated differently. Under SECURE 2.0 section 325, designated Roth accounts in employer plans, including the Roth TSP, are not subject to lifetime RMDs for tax years beginning after December 31, 2023 (Source: IRS RMD FAQs, 2025). For a fuller treatment, see the Q3 Advisors guide on required minimum distributions for 2026.
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Q3 Advisors is a registered investment adviser focused on retirement tax planning. This article is educational and is not advice; for guidance on your own circumstances, consult a qualified tax or financial professional.
Frequently asked questions
What is a thrift savings plan and how does it work?
A Thrift Savings Plan is the federal government’s defined contribution retirement plan for federal employees and uniformed-service members. Participants contribute through payroll deduction into low-cost funds, eligible FERS employees receive agency contributions, and the balance grows with contributions plus earnings. Retirement income depends on those amounts, not a guaranteed formula (Source: TSP.gov, About the TSP, 2026).
Is a TSP the same as a 401(k)?
The TSP is the federal equivalent of a 401(k) and shares the same annual elective deferral limit, $24,500 for 2026 (Source: IRS newsroom, 2025). Both are defined contribution plans funded by payroll deduction with employer or agency contributions. Differences include the TSP’s specific fund menu, its very low administrative costs, and its FERS matching structure.
Can civilians open a Thrift Savings Plan?
Private-sector civilians cannot open a TSP. Eligibility is limited to federal government civilian employees and members of the uniformed services, including the Ready Reserve (Source: TSP.gov, About the TSP, 2026). People outside federal service generally use employer 401(k) plans and individual retirement accounts (IRAs) as comparable retirement savings vehicles instead.
What is the difference between traditional and Roth TSP?
Traditional TSP contributions are pre-tax and reduce current taxable income, with withdrawals taxed later as ordinary income. Roth TSP contributions are after-tax, and qualified withdrawals may be tax-free (Source: TSP.gov, Contribution Types, 2026). Participants can use both. Notably, all agency matching lands in the traditional balance, even for Roth contributors.
What are the five TSP funds?
The five core individual TSP funds are the G Fund (U.S. Treasury securities guaranteed by the government), the F Fund (bond index), the C Fund (large U.S. stock index), the S Fund (small-cap U.S. stock index), and the I Fund (international stock index) (Source: TSP.gov, Investment Options, 2026). Lifecycle (L) target-date funds blend these five.
Is the TSP a good investment?
Whether the TSP fits any individual depends on personal circumstances, so this is educational information rather than a recommendation. The plan is known for very low administrative expenses, a 2019 net expense ratio of 0.042% (Source: TSP.gov, Expenses and Fees, 2026), agency matching for eligible FERS employees, and a simple fund menu. Suitability may vary by goals, taxes, and risk tolerance.
What happens to my TSP when I leave federal service?
After leaving federal service, you can generally keep the TSP account if the vested balance is $200 or more, or roll it over to an IRA or another eligible employer plan (Source: TSP.gov, 2026). Matching vests immediately; the FERS automatic 1% typically vests after two to three years. Rollover tradeoffs in cost and protections can vary.
Sources
TSP.gov, About the Thrift Savings Plan: https://www.tsp.gov/about-the-thrift-savings-plan-tsp/
TSP.gov, Contribution Types: https://www.tsp.gov/making-contributions/contribution-types/
TSP.gov, Investment Options: https://www.tsp.gov/investment-options/
TSP.gov, Lifecycle Funds: https://www.tsp.gov/funds-lifecycle/
TSP.gov, Expenses and Fees: https://www.tsp.gov/tsp-basics/expenses-and-fees/
IRS newsroom, 401(k) limit increases to $24,500 for 2026: https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500
IRS, COLA increases for dollar limitations: https://www.irs.gov/retirement-plans/cola-increases-for-dollar-limitations-on-benefits-and-contributions
IRS Notice 2025-67: https://www.irs.gov/pub/irs-drop/n-25-67.pdf
IRS Publication 590-B (2025): https://www.irs.gov/publications/p590b
IRS, Retirement plan and IRA RMD FAQs: https://www.irs.gov/retirement-plans/retirement-plan-and-ira-required-minimum-distributions-faqs
