Reviewed by the Rank and Pay editorial team on June 28, 2026.
The best TSP fund for you depends on your timeline, risk tolerance, and retirement goals. The Thrift Savings Plan offers five individual funds and a series of Lifecycle (L) funds — all with some of the lowest expense ratios of any retirement account in the United States.
As of 2024, every TSP fund charges roughly 0.048% per year in administrative fees, according to the Federal Retirement Thrift Investment Board (FRTIB). That means you keep far more of your returns than you would in a typical 401(k).
This guide ranks every TSP fund and explains who each one is best for, so you can build a portfolio that fits your career stage and risk level.
Table of Contents
- How we ranked TSP funds
- G Fund — Government Securities
- F Fund — Fixed Income Index
- C Fund — Common Stock Index
- S Fund — Small Cap Stock Index
- I Fund — International Stock Index
- L Funds — Lifecycle Target-Date Funds
- TSP fund comparison table
- Best TSP funds to invest in 2026, by strategy
- Best TSP fund: our verdict
- Frequently asked questions
How we ranked TSP funds
We evaluated each TSP fund on four criteria: risk level, long-term return potential, expense ratio, and best investor type. We used FRTIB annual reports, TSP.gov fund sheets, and publicly available historical data. We do not recommend any single fund for everyone — your best TSP fund depends on your age, career length, and when you plan to retire.
G Fund — Government Securities Investment Fund
Best for: risk-averse investors and those nearing retirement
The G Fund invests exclusively in short-term U.S. Treasury securities specially issued to the TSP. It is the only TSP fund with no risk of loss. Your balance never goes down.
The G Fund earns a rate based on the weighted average yield of all outstanding Treasury notes and bonds with four or more years to maturity. In recent years that has ranged from about 2% to 4.5% annually, depending on the interest rate environment.
Strengths: Zero market risk. Government-backed. Good for capital preservation in retirement.
Limitations: Returns may not keep pace with inflation over long periods. Not suitable as the sole fund for young investors with decades before retirement.
Expense ratio: ~0.048% (2024)
F Fund — Fixed Income Index Investment Fund
Best for: investors who want bond exposure with more return than the G Fund
The F Fund tracks the Bloomberg U.S. Aggregate Bond Index. It holds a broad mix of U.S. government bonds, mortgage-backed securities, and corporate bonds.
The F Fund carries more risk than the G Fund because bond prices move inversely with interest rates. When rates rise sharply (as they did in 2022), the F Fund can lose value. Over long periods, the F Fund has historically outpaced the G Fund.
Strengths: Diversified bond exposure. Can serve as a stabilizer alongside stock funds. Higher long-term return potential than G Fund.
Limitations: Can lose value in rising-rate environments. Returns still lag stock funds over multi-decade horizons.
Expense ratio: ~0.048% (2024)
C Fund — Common Stock Index Investment Fund
Best for: long-term growth investors with 10+ years to retirement
The C Fund tracks the S&P 500 index, which holds the 500 largest U.S. publicly traded companies. It is the most widely used TSP fund and often the backbone of a growth-oriented TSP portfolio.
Historically, the S&P 500 has delivered average annual returns of around 10% over long periods, though past performance does not guarantee future results. Short-term volatility is common — the C Fund lost roughly 18% in 2022 before recovering in 2023 and 2024.
Strengths: Strong long-term growth potential. Immediate diversification across 500 U.S. companies. Aligns with the most widely tracked benchmark in investing.
Limitations: Subject to market swings. Should be paired with other funds to reduce concentration risk.
Expense ratio: ~0.048% (2024)
S Fund — Small Cap Stock Index Investment Fund
Best for: aggressive growth investors who want exposure beyond large-cap stocks
The S Fund tracks the Dow Jones U.S. Completion Total Stock Market Index. It covers the roughly 3,500 U.S. stocks NOT in the S&P 500 — mostly small- and mid-cap companies.
The S Fund has historically delivered higher long-term returns than the C Fund in some periods, but with greater volatility. Small-cap stocks tend to be more sensitive to economic cycles.
Strengths: Access to thousands of smaller companies the C Fund misses. High long-term growth potential. Complements the C Fund well.
Limitations: Higher volatility than C or F funds. Individual small-cap companies carry more bankruptcy risk than S&P 500 giants.
Expense ratio: ~0.048% (2024)
I Fund — International Stock Index Investment Fund
Best for: investors seeking global diversification beyond U.S. markets
The I Fund tracks the MSCI EAFE Index, which covers large- and mid-cap stocks in developed markets in Europe, Australasia, and the Far East — 21 countries in total.
The I Fund adds geographic diversification to a TSP portfolio. International stocks often move differently from U.S. stocks, which can reduce overall portfolio volatility. However, the I Fund also carries currency risk and has underperformed U.S. stocks over the past decade.
Strengths: True international diversification. Can outperform U.S. markets during periods when the dollar weakens. Reduces home-country bias.
Limitations: Currency fluctuations affect returns. Has lagged U.S. markets significantly in recent years. Does not include emerging markets (China, India, Brazil, etc.).
Expense ratio: ~0.048% (2024)
L Funds — Lifecycle Target-Date Funds
Best for: investors who want a "set it and forget it" approach
The L Funds automatically blend the five individual funds and gradually shift toward more conservative allocations as the target date approaches. Available options include L Income, L 2025, L 2030, L 2035, L 2040, L 2045, L 2050, L 2055, L 2060, and L 2065.
Each L Fund holds a different mix of the G, F, C, S, and I funds. Younger investors in L 2055 or L 2065, for example, hold a heavy stock allocation. Investors close to retirement in L Income hold mostly G and F Fund.
L Fund highlights
- L Income: For investors already in retirement. Mostly G and F Fund. Lowest risk.
- L 2025: For investors retiring around 2025. Conservative mix shifting to L Income.
- L 2030–L 2045: Moderate mixes for mid-career service members.
- L 2050–L 2065: Aggressive stock-heavy mixes for early-career investors with decades to retirement.
Key advantage: Automatic rebalancing. The FRTIB adjusts the mix daily so you never have to manually rebalance.
Key limitation: The L Funds include the I Fund, which has been a drag on performance recently. Some investors prefer to build their own allocation using just C and S funds.
TSP fund comparison table
| Fund | What it tracks | Risk level | Return potential | Best for |
|---|---|---|---|---|
| G Fund | U.S. Treasury securities | Very low (no loss) | Low (~2–4.5%) | Near-retirement, capital preservation |
| F Fund | Bloomberg U.S. Aggregate Bond Index | Low-moderate | Low-moderate | Bond diversification |
| C Fund | S&P 500 | Moderate-high | High (long-term) | Long-term growth, core holding |
| S Fund | DJ U.S. Completion Index | High | High (long-term) | Aggressive growth, C Fund complement |
| I Fund | MSCI EAFE (international) | Moderate-high | Moderate-high | Global diversification |
| L Funds | Blended (all 5 funds) | Varies by target date | Varies by target date | Hands-off investors |
Best TSP funds to invest in 2026, by strategy
The best TSP fund to invest in for 2026 depends on your time horizon, not on which fund posted the highest past return. A 25-year-old with 30 years to retirement and a 60-year-old drawing down in five years should hold very different mixes of the same five funds. Below are four common horizons and a starting allocation for each — a framework, not personalized advice.
Decades from retirement (aggressive growth)
Investors with 20+ years until retirement can afford a stock-heavy TSP allocation and ride out volatility. A common aggressive mix is roughly 60% C Fund, 20% S Fund, 20% I Fund, with little or no G/F Fund. The C and S Funds capture U.S. large- and small-cap growth; the I Fund adds international diversification. The simplest one-fund version of this is the L 2055, L 2060, or L 2065 Lifecycle fund, which holds a similar stock-heavy blend and shifts automatically as retirement nears.
Mid-career (balanced growth)
Investors 10–20 years out usually trim risk while still leaning toward stocks. A balanced starting mix is around 50% C, 15% S, 15% I, 20% G — enough equity to keep growing, with a bond/G-Fund cushion to soften a bad year. The matching one-fund choice is the L 2040 or L 2045.
Near retirement (capital preservation)
Within five years of retirement, protecting the balance matters more than maximizing it. Many members shift toward 30% C, 5% S, 5% I, 40% G, 20% F, raising the G and F Funds so a market drop right before retirement can't force a delay. The L 2030 or L Income fund mirrors this more conservative blend.
In retirement (income and stability)
Retirees taking withdrawals typically hold the most conservative mix — the L Income fund is built for exactly this, keeping roughly 70–80% in the G and F Funds with a small equity sleeve so the balance still grows enough to outpace inflation. Keeping one to two years of planned withdrawals in the G Fund lets you avoid selling stocks during a downturn.
The single most common 2026 mistake
The costliest TSP mistake is sitting in the G Fund by default for decades. The G Fund never loses money, which feels safe, but its returns often barely beat inflation — so a young saver parked there can retire with far less than a peer who accepted short-term stock swings. If you're early in your career and unsure, a dated Lifecycle (L) fund is almost always a better default than 100% G, because it puts you in an age-appropriate stock allocation without any rebalancing on your part.
These allocations are illustrative starting points for 2026, not individualized recommendations. Your own mix should reflect your risk tolerance, other retirement accounts (including a Roth IRA or a spouse's plan), and your target retirement date. Consider the Blended Retirement System match before anything else — always contribute at least enough to capture the full 5% government match.
Best TSP fund: our verdict
There is no single best TSP fund — but there are clear winners by investor type.
- Best overall for young service members (20+ years to retirement): C Fund or a 60% C / 20% S / 20% I split. Maximum growth potential at minimal fees.
- Best for hands-off investors: The appropriate L Fund matching your expected retirement year. Set it once and the FRTIB does the rest.
- Best for capital preservation: G Fund. Ideal when you are within 5 years of retirement or drawing from your account.
- Best for aggressive growth: C Fund + S Fund combination. Together they cover the entire U.S. stock market at rock-bottom cost.
- Best for international exposure: I Fund as a small complement (10–15%) to a C+S core. Use sparingly given recent underperformance.
A common allocation for mid-career service members is the "C/S/I" blend — roughly 60% C Fund, 20% S Fund, 20% I Fund — which mirrors a total world stock market approach at TSP's famously low fees.
To learn more about how the TSP fits into your military retirement picture, see our guides to the Roth vs Traditional TSP decision, TSP withdrawal strategies, and the Blended Retirement System explained. For how your TSP complements your pension, visit the military retirement pay guide.