TSP vs 401(k): A Detailed Comparison for Federal Employees

TSP vs 401(k): Understanding the Key Differences

The Thrift Savings Plan (TSP) and the 401(k) are both employer-sponsored defined-contribution retirement plans, but they serve different workforces. The TSP is exclusively for federal employees and members of the uniformed services, while 401(k) plans are offered by private-sector employers. Although they share the same fundamental tax-advantaged structure, the differences between them — particularly in costs, fund options, and administration — are significant.

For federal employees who may be considering a move to the private sector, or private-sector workers contemplating federal employment, understanding the TSP vs 401(k) comparison is essential for making informed career and financial decisions.

The TSP's Biggest Advantage: Ultra-Low Fees

If there is one fact that every federal employee should know about their retirement plan, it is this: the TSP has some of the lowest investment fees of any retirement plan in the world. This is not an exaggeration — it is a mathematical reality that has enormous implications for long-term wealth accumulation.

TSP Expense Ratios

The TSP's net administrative expense ratio has historically been in the range of 0.04% to 0.06% per year. This means that for every $10,000 invested, you pay roughly $4 to $6 annually in fees. This is lower than even the cheapest retail index funds and ETFs available to individual investors.

Typical 401(k) Expense Ratios

Private-sector 401(k) plans vary enormously in cost, but studies consistently show that the average 401(k) participant pays significantly more:

• Large employer plans: Average expense ratios of 0.30%–0.50% are common at large companies with negotiating leverage
• Small employer plans: Expense ratios of 0.80%–1.50% or higher are not unusual at smaller companies
• Plans with actively managed funds: Some 401(k) plans offer primarily actively managed funds with expense ratios exceeding 1.00%
• Additional plan-level fees: Many 401(k) plans charge recordkeeping, administrative, or advisory fees on top of fund-level expenses

The Impact Over a Career

The difference between 0.05% and 0.50% may sound trivial, but compounding makes it substantial. Consider two employees who each invest $500 per month for 30 years, earning an average return of 7% before fees:

• TSP at 0.05% fees: Final balance of approximately $580,000
• 401(k) at 0.50% fees: Final balance of approximately $540,000
• 401(k) at 1.00% fees: Final balance of approximately $499,000

The TSP participant ends up with $40,000 to $80,000 more than the 401(k) participant — solely because of lower fees. This is money that stays in your account compounding for your retirement rather than being paid to fund managers and plan administrators.

Fund Options: Simplicity vs. Choice

TSP Fund Lineup

The TSP offers a deliberately simple lineup of investment options:

• G Fund: Government Securities (special Treasury bonds)
• F Fund: Fixed income (Bloomberg U.S. Aggregate Bond Index)
• C Fund: Common stock (S&P 500 Index)
• S Fund: Small/mid-cap stock (Dow Jones U.S. Completion TSM Index)
• I Fund: International stock (MSCI EAFE Index)
• L Funds: Lifecycle target-date funds (blends of the above five funds)

With the mutual fund window introduced in 2022, TSP participants can also access a broader range of mutual funds for an additional fee, though the core funds remain the primary investment vehicle for most participants.

Typical 401(k) Fund Lineup

Private-sector 401(k) plans vary widely in their fund offerings:

• Best plans: Offer low-cost index funds similar to TSP funds, plus target-date funds and perhaps a few additional options
• Average plans: Offer a mix of actively managed and index funds, with varying quality and cost
• Worst plans: Offer only high-cost actively managed funds or limited options with embedded fees

While having more choices sounds appealing, research shows that too many options can lead to "choice paralysis" and suboptimal decisions. The TSP's streamlined approach has the advantage of simplicity — most participants can build an excellent portfolio using just two or three funds.

Employer Matching Contributions

TSP Matching for FERS Employees

Federal employees under the Federal Employees Retirement System (FERS) receive a generous matching structure:

• Automatic 1% contribution: The agency contributes 1% of your basic pay regardless of whether you contribute anything. This is free money with no action required.
• Dollar-for-dollar match on the first 3%: If you contribute at least 3% of your pay, the agency matches every dollar.
• 50-cent match on the next 2%: Contributions from 3% to 5% of pay are matched at 50 cents per dollar.
• Total matching at 5% contribution: When you contribute 5% of your pay, you receive a total of 5% from the agency (1% automatic + 3% match + 1% match).

This means the effective match rate is 100% on the first 5% you contribute when you account for the automatic 1%. Vesting is immediate — these matching contributions are yours from day one.

Typical 401(k) Matching

Private-sector matching varies enormously by employer:

• Common formula: 50% match on the first 6% of salary (equivalent to 3% employer contribution)
• Generous plans: Dollar-for-dollar match on the first 4%–6% of salary
• Some employers: Offer no match at all
• Vesting schedules: Many 401(k) plans require 3–6 years before employer contributions fully vest. If you leave before the vesting period, you forfeit some or all of the employer match.

The TSP's immediate vesting is a significant TSP advantage over many private-sector plans, particularly for employees who may change jobs before a typical vesting period ends.

Contribution Limits

The annual contribution limits for the TSP and 401(k) are identical, as both fall under the same IRS rules (Section 402(g) of the Internal Revenue Code). For 2026:

• Regular contribution limit: $24,500 (the same for both TSP and 401(k))
• Catch-up contributions (age 50+): An additional $8,000 per year
• Enhanced catch-up (ages 60–63): An additional $11,250 per year under the SECURE 2.0 Act provisions

These limits apply to employee contributions only. Employer matching contributions do not count toward these limits.

Roth Options

Both the TSP and most modern 401(k) plans offer a Roth option:

• TSP Roth: Available since 2012, allowing participants to make after-tax Roth contributions alongside or instead of traditional pre-tax contributions
• 401(k) Roth: Widely available in private-sector plans, though not all employers offer it

The Roth contribution feature works identically in both plans — contributions are made with after-tax dollars, and qualified withdrawals in retirement are tax-free. The SECURE 2.0 Act also eliminated the requirement for Roth 401(k) holders to take required minimum distributions (RMDs), aligning Roth 401(k) and Roth TSP rules more closely with Roth IRAs.

Loan Provisions

TSP Loans

The TSP offers two types of loans:

• General purpose loan: Repayment period of 1 to 5 years, no documentation required
• Residential loan: Repayment period of 1 to 15 years, requires documentation of a primary residence purchase
• Interest rate: The G Fund rate at the time the loan is processed
• Minimum loan: $1,000
• Maximum loan: The lesser of 50% of your vested balance or $50,000 (reduced by your highest outstanding loan balance in the prior 12 months)

401(k) Loans

Most 401(k) plans also offer loans, though terms vary:

• Not all plans offer loans — some employers choose not to include this feature
• Similar IRS-mandated limits apply ($50,000 or 50% of vested balance)
• Interest rates vary by plan and are typically prime rate plus 1%–2%
• Some plans charge origination or maintenance fees for loans

The TSP's loan provisions are generally more favorable and standardized compared to the wide variation found in 401(k) plans.

Portability and Rollovers

Leaving Federal Service

When you leave federal employment, you have several options for your TSP balance:

• Leave it in the TSP (you can keep your account open and continue benefiting from low fees)
• Roll it into an IRA
• Roll it into a new employer's 401(k)
• Take a taxable distribution (subject to taxes and potential penalties)

Leaving Private-Sector Employment

Similar options exist for 401(k) participants, but there is an important consideration: after leaving, you may want to roll your 401(k) into an IRA to escape high fees or limited fund options. With the TSP, the ultra-low fees mean there is a strong argument for keeping your money in the TSP even after leaving federal service.

Additionally, the TSP accepts rollovers from 401(k) plans and traditional IRAs, allowing former private-sector employees who join federal service to consolidate their retirement savings in the TSP's low-cost environment.

Administration and Oversight

The TSP is administered by the Federal Retirement Thrift Investment Board (FRTIB), an independent federal agency. This government oversight means:

• The plan operates with a fiduciary duty to participants
• Fees are kept extremely low because the plan is not operated for profit
• Investment options are selected based on participant interests, not revenue considerations
• The plan is not subject to the risk of employer bankruptcy affecting retirement savings

Private-sector 401(k) plans are governed by ERISA (Employee Retirement Income Security Act), which provides important protections but does not guarantee the same cost efficiency as the TSP's non-profit structure.

Side-by-Side Comparison Summary

• Expense ratios: TSP wins decisively (0.04%–0.06% vs. 0.30%–1.50%+ for most 401(k) plans)
• Fund options: 401(k) plans offer more variety; TSP offers simplicity and quality
• Employer match: TSP offers immediate vesting and a predictable match; 401(k) varies widely
• Contribution limits: Identical (same IRS rules apply)
• Roth option: Both offer it, though not all 401(k) plans include it
• Loans: TSP offers standardized, favorable terms; 401(k) varies by plan
• Portability: Both are portable, but TSP's low fees make it attractive to keep even after separation

Key Takeaways

• The TSP's ultra-low expense ratios are its single greatest advantage, potentially saving participants tens of thousands of dollars over a career compared to the average 401(k)
• The TSP's matching structure with immediate vesting is more favorable than many private-sector plans
• While 401(k) plans may offer more investment choices, the TSP's core funds cover all major asset classes at minimal cost
• Federal employees should appreciate the TSP as one of the most valuable benefits of federal employment
• If you leave federal service, carefully consider keeping your balance in the TSP rather than rolling to a higher-cost alternative

Disclaimer: This content is for educational and informational purposes only and does not constitute financial, investment, or tax advice. The Thrift Savings Plan is administered by the Federal Retirement Thrift Investment Board. Contribution limits and tax rules are subject to change and are based on IRS regulations current at the time of writing. Individual 401(k) plans vary significantly, and the comparisons here reflect general patterns rather than any specific plan. You should consult a qualified financial advisor before making any investment or retirement planning decisions. Apex Equity is not affiliated with the Federal Retirement Thrift Investment Board or the U.S. government.

Frequently Asked Questions

Q: Is the TSP better than a 401(k)?

A: In most cases, yes. The TSP's ultra-low expense ratios (0.05% vs 0.30-1.50% for typical 401(k) plans) can save you tens of thousands of dollars over a career. The TSP also offers immediate vesting and a standardized, favorable matching structure.

Q: Can I roll my 401(k) into the TSP?

A: Yes. The TSP accepts rollovers from 401(k) plans and traditional IRAs. This allows former private-sector employees who join federal service to consolidate their retirement savings in the TSP's low-cost environment.

Q: Should I keep my TSP after leaving federal service?

A: Often yes. The TSP's ultra-low fees make it one of the best places to keep retirement savings even after separation. Compare the fees carefully before rolling to an IRA or new employer's plan.