Will TSP Returns Continue to Grow in December?
Investors hoping to see more record highs before the start of 2026 have some hope that their wish may come true this year.
Since 1950, when the S&P 500 rises 2% or more during Thanksgiving week, it has continued to rise in December more than 80% of the time. Here is a reason for optimism that this will happen this year. The S&P 500 just had its best performance during the holiday week since 2008.
The late November stock market rally pushed stocks to near-record highs. Optimism about a potential Federal Reserve interest-rate cut in December was the impetus for reversing an earlier mid-month market slump.
The S&P 500 (the index on which the C Fund is based) is now near a record set in late October. The C Fund is now up 17.78% for the year. The I Fund continues to deliver the best returns among these TSP stock funds in 2025.
Here are TSP returns for core stock funds in the Thrift Savings Plan (TSP) in 2025 through the end of November:
| C Fund | 17.78% |
| S Fund | 11.97% |
| I Fund | 28.54% |
TSP Returns for Funds in November 2025, Year-to-Date and 12-Month Returns
| Fund | Month-do-Date | Year-to-Date | 12-Month |
|---|---|---|---|
| G Fund | 0.34% | 4.08% | 4.46% |
| F Fund | 0.64% | 7.49% | 5.65% |
| C Fund | 0.24% | 17.78% | 14.96% |
| S Fund | -0.45% | 11.97% | 4.08% |
| I Fund | 0.42% | 28.54% | 24.91% |
| L Income | 0.35% | 8.80% | 8.08% |
| L 2030 | 0.31% | 14.35% | 12.22% |
| L 2035 | 0.30% | 15.39% | 12.99% |
| L 2040 | 0.30% | 16.38% | 13.70% |
| L 2045 | 0.29% | 17.23% | 14.31% |
| L 2050 | 0.28% | 18.05% | 14.91% |
| L 2055 | 0.23% | 20.65% | 16.87% |
| L 2060 | 0.23% | 20.66% | 16.87% |
| L 2065 | 0.23% | 20.66% | 16.87% |
| L 2070 | 0.23% | 20.67% | 16.90% |
| L 2075 | 0.23% | N/A | N/A |
Summary of 2025 Core TSP Fund Performance, through November
According to TSPDataCenter as of November 28, 2025:
- I Fund: up ~28.5 % YTD — the strongest performer among the primary funds.
- C Fund (large U.S. companies): up ~17.8 % YTD.
- S Fund (small- & mid-size U.S. companies): up ~12.0 % YTD.
- F Fund (bonds): up ~7.5 % YTD.
- G Fund (government securities — basically the “safe” fund): up ~4.1 % YTD.
What This Means for Your Investments — A Quick Take for TSP Investors
- The I Fund is the clear standout in 2025. Its near-29% return shows that international equities (non-U.S.) have outperformed U.S.-based funds by a wide margin.
- Among U.S. equity funds, the C Fund has done very well — reflecting strong performance among large-cap companies. The S Fund also gained, but lagged behind the C Fund and the I Fund.
- The fixed-income F Fund and low-risk G Fund provided modest but steady gains — useful for investors prioritizing stability over aggressive growth.
- The slight pullback in the S Fund in November suggests greater volatility in small- and mid-cap U.S. stocks than in the broader large-cap or international markets.
Which Investors “Won” With TSP Investments — and Which Ones Stayed Safe
- Best for growth: I Fund (international equities) — best mix of return and equity-style gains.
- Best U.S.-stock exposure: C Fund — solid large-cap returns without the additional volatility of small caps or international currency exposure.
- Best for stability / conservative approach: G Fund and F Fund — lower return but minimal volatility and capital preservation.
Summary
In January, FedSmith posted an article with the headline 2024 TSP Performance: Two Consecutive Record-Setting Years for Leading Stock Funds. In 2024, the C Fund (24.96%) and the S Fund (16.93%) had the best returns while the I Fund lagged at 4.27%.
While there is another month to go that will change these results, the I Fund has made terrific gains (28.54%) for those investing in it and is likely to end up as the biggest winner of the year, despite its monthly returns showing lower returns as the year has progressed.
The summary of each TSP Fund for the year shows how your investing decisions can influence your eventual retirement income. No one can correctly predict the best stock investments for the future every time.
The best we can do is look at how stocks have reacted in the past under similar conditions. In short, do not expect to come out on top based on guessing what the future will bring. The most successful TSP investors, especially those who have achieved TSP millionaire status, invest for the long term and use the TSP stock funds as their investment vehicle.
