TSP funds guide: what the G, C, F, S, I and L Funds are and how they differ

By the OnPAR Federal Retirement Education editorial team · Last updated November 7, 2026

Related: TSP guides · TSP Roth vs traditional · TSP withdrawal options · TSP calculator

Short answer: The TSP has five individual funds (G, F, C, S and I) and eleven L Funds that mix those five for you [1] [9]. The G Fund holds special U.S. Treasury securities and its value does not fluctuate. F is bonds, C is the S&P 500, S is small and mid-size U.S. companies, and I is international stocks [1]. The more stock exposure, the higher the long-term growth potential and the bigger the swings. This page is education, not investment advice.

1. The five individual funds at a glance

Risk labels and expense ratios (as of December 31, 2025) are from the TSP [1]. The per-$100,000 column is simple arithmetic on those ratios.

2. What each fund does

G Fund: the “can’t lose principal” fund

The G Fund is invested in Treasury securities specially issued to the TSP. There is no credit risk, and the value of G Fund securities doesn’t fluctuate; only the interest rate changes [2]. The TSP notes it is subject to inflation risk: your money may not grow enough to offset the rise in prices [2]. The TSP describes it as the choice if you want all or part of your account “completely protected from loss” [2].

F Fund: bonds

By law the F Fund must be invested in fixed-income securities. It tracks a broad index that held 13,630 notes and bonds on December 31, 2025 [3]. The F Fund lost money in 2022 (see the table below), so bonds are not risk-free.

C Fund: large U.S. stocks

The S&P 500 is made up of 500 large U.S. companies, representing approximately 88% of the market value of U.S. stock markets [4].

S Fund: small and mid-size U.S. stocks

The S Fund covers U.S. stocks that are not in the S&P 500. The TSP notes the C, S and I Funds track different segments of the stock market without overlapping [5].

I Fund: stocks outside the U.S.

As of December 31, 2025 the index held over 5,000 stocks across 44 countries (21 developed and 23 emerging markets) [6]. I Fund returns also move with the value of the U.S. dollar against other currencies (currency risk) [6]. The benchmark changed: the TSP completed the switch to its current international index in October 2024 [7], so older articles that say “I Fund = EAFE” are out of date.

3. The L Funds: a mix chosen for you

Each of the eleven L Funds (L Income and L 2030 through L 2075) is a diversified mix of the G, F, C, S and I Funds. They let you hold your whole account in one fund [9]. The mix is rebalanced every day and the target allocation is adjusted quarterly, becoming more conservative (less C, S and I; more G and F) as the date approaches [9].

• L 2050 is for people born between 1985 and 1989, or planning to start withdrawals between 2048 and 2052. It rolls into the L Income Fund automatically in July 2050. Total expense ratio 0.041% [9].
• L Income is for people born before 1965, already withdrawing, or planning to begin before 2028. It doesn’t change quarterly. It is moving to new targets, with the transition complete in 2028. Total expense ratio 0.035% [8].

The TSP points you to the L Fund that matches your birth year or planned withdrawal date. If you also hold individual funds, you are making your own allocation on top of what the L Fund does, so check your account to see exactly what you hold.

4. How the funds have actually behaved: 2021 to 2025

Calendar-year returns from the TSP fact sheet [10]. The last column shows what $10,000 invested at the start of 2021 would have become by the end of 2025 if returns compounded each year (our arithmetic; it ignores contributions and withdrawals). I Fund returns before the 2024 benchmark switch tracked the older international index.

What to notice: the G Fund was positive every year and finished ahead of the F Fund, but behind the C, S and I Funds. In 2022 the F, C, S and I Funds all lost money (F -12.83%, C -18.13%, S -26.26%, I -13.94%). In 2025 the I Fund returned +32.45% and the C Fund +17.85%. Past performance does not guarantee future results [2]. Current and longer-term returns are on the TSP’s rates of return page [11].

5. Questions to ask yourself before changing funds

1. When will I need this money? Money needed within a few years is different from money for 20 years from now.
2. How would I feel about a year like 2022? A fund can drop sharply. The G Fund didn’t.
3. Am I diversified or concentrated? The TSP notes that investing in all segments of the stock market reduces your exposure to market risk compared with just one [4].
4. Do I need an L Fund’s hands-off approach? It rebalances for you daily [9].
5. Which balance is the money in? Traditional or Roth changes the tax picture, not the funds. See TSP Roth vs traditional.

What to do next

1. Log in to your TSP account and look at your current allocation (which funds and what percent).
2. Check the expense ratios and risk labels on TSP.gov [1].
3. If you change anything, check TSP.gov for how to change where future contributions go and how to move your existing balance; those are handled separately.
4. Already retired or close? Read TSP withdrawal options and try the TSP withdrawal calculator.
5. More: TSP guides, FERS vs TSP, and TSP limits for 2027.

Questions and answers

What are the TSP G, C, F, S, I and L funds?

G is U.S. Treasury securities issued to the TSP (value does not fluctuate), F tracks a broad U.S. bond index, C tracks the S&P 500, S tracks small and mid-size U.S. stocks outside the S&P 500, and I tracks international stocks. The eleven L Funds (L Income and L 2030 to L 2075) are mixes of those five that become more conservative over time.

Which TSP fund is the safest?

The TSP labels the G Fund as low risk: its value does not fluctuate and principal and interest are guaranteed by the U.S. government. Its main risk is inflation, because returns may not keep up with rising prices.

What does the TSP I Fund track now?

The MSCI ACWI IMI ex USA ex China ex Hong Kong Index. The TSP finished switching to this benchmark in October 2024; before that the I Fund tracked the MSCI EAFE index.

What are the TSP fund fees?

As of December 31, 2025, total expense ratios were 0.034% for the G Fund, 0.035% for F and C, 0.048% for I and 0.051% for S. That is $34 to $51 a year per $100,000.

Official sources

1. TSP: Individual funds (objectives, risk, expense ratios)
2. TSP: G Fund
3. TSP: F Fund
4. TSP: C Fund
5. TSP: S Fund
6. TSP: I Fund
7. TSP: I Fund benchmark index change complete (Oct 30, 2024)
8. TSP: L Income Fund
9. TSP: L 2050 Fund (example L Fund page)
10. Thrift Savings Plan Fact Sheet (annual fund returns), as published in USPS Postal Bulletin 22706
11. TSP: Rates of return

Checked against IRS, OPM, SSA and TSP sources on November 6, 2026. Education only, not legal, tax or financial advice. Your own situation may differ: check with a tax professional, OPM, the TSP or your state tax office. Not affiliated with OPM, the IRS, SSA, the TSP or any government agency.