As of August 2026, the TSP G Fund interest rate is 4.875%. The rate is calculated monthly, based on the average yield of all U.S. Treasury securities with 4 or more years to maturity. The chart and table below show the recent history of the G Fund rate.
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This month’s G Fund interest rate becomes next month’s TSP loan rate — see the current TSP loan interest rate, its full history, and how it compares to bank borrowing.
| Date | Interest Rate |
|---|---|
| August 2026 | 4.875% |
| July 2026 | 4.500% |
| June 2026 | 4.500% |
| May 2026 | 4.500% |
| April 2026 | 4.375% |
| March 2026 | 4.000% |
| February 2026 | 4.250% |
| January 2026 | 4.250% |
| December 2025 | 4.125% |
| November 2025 | 4.125% |
| October 2025 | 4.250% |
| September 2025 | 4.250% |
The G Fund interest rate is currently 4.875%. But it returned over 9 percent per year shortly after it was launched in the late 1980s:
The G Fund compares very favorably to other risk-free investments. In the charts above and below you can see that the interest rate on the G Fund is almost always higher than the 3-month Treasury Bill yield. There are some exceptions though — notice how the G Fund interest rate was lower than that on Treasury Bills during the inflation spike in 2023-2024:
Overall, the TSP G Fund has held up well against inflation.
The TSP G Fund will not lose money — its returns are guaranteed by the U.S. Government. That makes it very different from a typical bond fund, where your principal fluctuates with the rise and fall of interest rates. The chart below shows the historical performance of the TSP G Fund, and is updated every business day with the latest TSP G Fund price:
The G Fund has earned a compound annualized return of 4.7% since its launch in April 1987. Its year-to-date return is 2.7%, and its 1-year return is 4.4%. A $1,000 investment in 1987 would be worth $6,049 today.