TSP Funds
Every Thrift Savings Plan fund, with official descriptions and live year-to-date returns.
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Year-to-date total returns are sourced from official daily TSP share prices. The Lifecycle (L) funds are covered in the Lifecycle funds guide.
G Fund — Government Securities
Benchmark: weighted average of outstanding U.S. Treasury medium- & long-term rates
The G Fund is invested in short-term U.S. Treasury securities specially issued to the TSP. Principal and interest are guaranteed by the U.S. government, so the share price never goes down — there is no risk of losing what you put in.
- What it earns: interest at a rate tied to the average yield of longer-term Treasuries, which usually beats short-term rates.
- Best for: money you can't afford to risk, and shifting toward as you near retirement.
- The trade-off: the lowest long-run growth of any TSP fund, so leaning on it for decades risks not outpacing inflation.
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F Fund — Fixed Income Index
Benchmark: Bloomberg U.S. Aggregate Bond Index
The F Fund tracks a broad index of U.S. investment-grade bonds — government, corporate, and mortgage-backed. It usually earns a bit more than the G Fund over time, but unlike the G Fund its price can fall, especially when interest rates rise.
- Why hold it: diversification — bonds often behave differently from stocks.
- Main risk: rising interest rates (and, to a lesser degree, credit risk).
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C Fund — Common Stock Index
Benchmark: S&P 500 Index
The C Fund tracks the S&P 500 — the 500 largest U.S. companies. It's the classic "U.S. stock market" exposure and, historically, a primary engine of long-term TSP growth, along with most of the short-term ups and downs.
- Best for: long time horizons where you can ride out volatility.
- Note: heavily weighted toward the largest companies, so it moves with the mega-caps.
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S Fund — Small Cap Stock Index
Benchmark: Dow Jones U.S. Completion Total Stock Market Index
The S Fund holds the rest of the U.S. stock market — the small- and mid-cap companies not in the S&P 500. Pairing the C and S funds gives you essentially the entire U.S. market.
- Character: historically a bit more volatile than the C Fund, with strong long-run growth potential.
- Tip: many investors hold C and S together (roughly 4:1 mirrors the total market).
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I Fund — International Stock Index
Benchmark: MSCI ACWI IMI ex USA ex China ex Hong Kong Index
The I Fund invests in stocks of companies outside the United States, spanning developed and emerging markets. In 2024 its benchmark broadened to the MSCI ACWI IMI ex USA ex China ex Hong Kong Index, adding emerging-market and small-cap exposure.
- Why hold it: global diversification beyond the U.S. market.
- Extra risk: currency movements can help or hurt returns.
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Want the Lifecycle funds? Read the L Funds guide →
Educational only — not financial advice. Year-to-date returns are computed from official daily TSP share prices (tsp.gov) and update each business day; figures may lag the latest close. Benchmarks and fund details per tsp.gov. CalculateTSP is independent and not affiliated with the U.S. Department of Defense, DFAS, or the Federal Retirement Thrift Investment Board.