C and S Fund Post Four Months of Positive TSP Returns
August 2025 ended with positive returns in the major American stock indices. This was the fourth consecutive month of gains. The results were likely driven by strong corporate earnings and increasing investor confidence in the stock market, as well as anticipation of a potential Federal Reserve interest rate cut in September.
The overall success of stocks in the major stock indices is also reflected in the Thrift Savings Plan (TSP) performance for August 2025. This is the 4th consecutive month that the C and S Funds have had positive returns.
The I Fund has had a positive return in three of the last four months. The I Fund is also significantly ahead in 2025 with the highest year-to-date return.
Having these funds each finish in positive territory for four more consecutive months is uncommon. While these two funds are US stock funds, the C Fund represents large-cap stocks through the S&P 500 index. The S Fund covers the US stock market outside the S&P 500, mainly smaller companies.
Last Three Consecutive Simultaneous Winning Streaks for C and S Funds (4 or More Months)
| Fund | C Fund | S Fund |
| August 2025 | 2.03% | 4.08% |
| July 2025 | 2.24% | 2.53% |
|---|---|---|
| June 2025 | 5.08% | 5.40% |
| May 2025 | 6.29% | 7.21% |
| Fund | C Fund | S Fund |
| August 2020 | 7.19% | 7.20% |
|---|---|---|
| July 2020 | 5.64% | 5.71% |
| June 2020 | 1.99% | 4.00% |
| May 2020 | 4.76% | 8.79% |
| April 2020 | 12.81% | 15.81% |
| Month | C Fund | S Fund |
| December 2019 | 3.01% | 2.15% |
|---|---|---|
| November 2019 | 3.63% | 4.54% |
| October 2019 | 2.16% | 1.93% |
| September 2019 | 1.87% | 1.06% |
For the last 12 months, the S Fund (15.84%) has just edged out the C Fund’s yearly return (15.83%).
TSP investors who may be wondering why the I Fund has done so much better than the other two core TSP stock funds should check out this article for a comprehensive summary of the reasons for the I Fund’s strong performance this year.
TSP Performance for August 2025, Year-to-Date, and 12-Months
| Fund | Month | Year-to-Date | 12-Month |
|---|---|---|---|
| G Fund | 0.37% | 2.98% | 4.42% |
| F Fund | 1.19% | 4.99% | 3.15% |
| C Fund | 2.03% | 10.76% | 15.83% |
| S Fund | 4.08% | 8.96% | 15.84% |
| I Fund | 3.95% | 21.50% | 12.80% |
| L Income | 1.12% | 6.24% | 7.37% |
| L 2030 | 1.97% | 10.04% | 10.92% |
| L 2035 | 2.14% | 10.71% | 11.51% |
| L 2040 | 2.29% | 11.37% | 12.10% |
| L 2045 | 2.42% | 11.93% | 12.60% |
| L 2050 | 2.55% | 12.47% | 13.10% |
| L 2055 | 2.95% | 14.19% | 14.88% |
| L 2060 | 2.95% | 14.19% | 14.88% |
| L 2065 | 2.95% | 14.19% | 14.88% |
| L 2070 | 2.95% | 14.21% | 14.88% |
| L 2075 | 2.95% | 3.92% | N/A |
TSP Factoids
The TSP continues to grow, with $1.017 trillion in total assets and $81 billion in Roth accounts. As of December 31, 2024, the program has $963 billion in assets and $73 billion in Roth assets.
And, as of July 31, 2025, the average FERS balance in the TSP was $205,373 with 4,159,982 accounts. The average Roth balance for FERS employees based on the latest data is $35,627. The TSP has more than 7.2 million total accounts as of the end of July including beneficiaries, CSRS, uniformed services legacy accounts and BRS uniformed services.
Participant Allocation of TSP Assets
The percentage and total investments by TSP investors in various stock funds and the G Fund change over time. Here is how TSP participants allocated their funds as of the end of July 2025 compared to December 31, 2024.
During 2025, TSP investors are putting more total dollars into the C Fund, but the percentage of investment has declined over the year (from 36.1% to 34.9%). The percentage going into the S Fund now (8.8%) is also lower than what was invested at the end of 2024 (10.2%). The percentage allocated to the I Fund has increased to 4.3% (from 3.2%), and the total dollars invested in this Fund have also risen.
The G Fund percentage has also gone up this year to 24.3% from 23.6% at the end of 2024.
| Fund | Date | Percent | Total $ (billions) |
| C | 12/31/24 | 36.1 | 348.1 |
| S | 12/31/24 | 10.2 | 98.3 |
| I | 12/31/24 | 3.2 | 30.9 |
| G | 12/31/24 | 23.6 | 227.8 |
| C | 7/31/25 | 34.9 | 355.1 |
| S | 7/31/25 | 8.8 | 89.5 |
| I | 7/31/25 | 4.3 | 43.7 |
| G | 7/31/25 | 24.3 | 247.1 |
Based on the very high returns for the I Fund in 2025, a higher percentage going into this Fund is not a surprise. The increase in the G Fund will surprise some investors, and the decline in the stock funds during 2025 may also be a surprise.
Stock investors often modify their investments based on their expectations for future stock returns. Perhaps that is how those TSP investors that are modifying their allocations are projecting into the future.
