2026 has been a volatile year for the stock market. Despite the volatility, the Thrift Savings Plan (TSP) is performing well and rewarding investors.
In April, the TSP’s core stock funds all posted excellent returns. The C Fund was up 10.49%, the S Fund was up 9.96%, and the I Fund was up 9.11%. Those would be good returns for an entire year, but these figures are only for April.
While TSP investors will love looking at their latest monthly TSP performance, and some will wonder if these are the best monthly TSP returns there have ever been, despite a 10.49% return, it is not the best month ever for the C Fund. In fact, it is only the fifth highest month there has ever been for C Fund returns.
And, of course, stocks go up, and they go down as well. While this is a good month to enjoy looking at your TSP returns, keep in mind that returns can go in the opposite direction at times. For perspective, here are the best and worst months ever for the C Fund.
Best and Worst Months for the C Fund
| Top 10 Best | Top 10 Worst | ||
| Month | Return | Month | Return |
| Apr 2020 | +12.81% | Oct 2008 | -16.83% |
| Dec 1991 | +11.418 | Aug 1998 | -14.47% |
| Nov 2020 | +10.95% | Mar 2020 | -12.40% |
| Oct 2011 | +10.93% | Sep 2002 | -10.87% |
| Apr 2026 | +10.49% | Feb 2009 | -10.64% |
| Mar 2000 | +9.74% | Sep 2022 | -9.21% |
| Apr 2009 | +9.58% | Feb 2001 | -9.12% |
| May 1990 | +9.44% | Dec 2018 | -9.03% |
| Jul 2022 | +9.22% | Sep 2008 | -8.94% |
| Nov 2023 | +9.12% | Apr 2022 | -8.72% |
What Led to the High Monthly TSP Returns?
The stock market and TSP returns in April were not random. These factors led to the monthly returns:
- Relief from geopolitical fear
- Strong earnings (especially tech and artificial intelligence)
- Solid—not spectacular—economic data
- Investors rushing back into stocks
Here is a simple explanation: March priced in a crisis that didn’t happen—April reversed it fast.
What This Means for TSP Participants
International events, investor relief (temporary or longer-lasting), and an economy growing in the first quarter of the year resulted in high TSP returns in April. In a very brief summation:
- C Fund (+10.49%): Driven by large-cap tech stocks + strong earnings
- S Fund (+9.96%): Boosted by broad risk-on sentiment
- I Fund (+9.11%): Lifted by global recovery and tech stock spillover
While the C Fund is the most popular TSP Fund (at least the Fund with the highest percentage of TSP investment allocations), all of the Funds in the TSP went up in April. The C Fund posted the highest monthly return, and the G Fund posted the lowest return (0.36%).
Here are the monthly returns for all of the TSP Funds.
TSP Performance for April 2026, Year-to-Date and 12-Month Returns
| TSP Fund | Current Month (%) | Year-to-Date (%) | 12-Month Trailing (%) |
|---|---|---|---|
| G Fund | 0.36% | 1.41% | 4.37% |
| F Fund | 0.12% | 0.16% | 4.07% |
| C Fund | 10.49% | 5.70% | 31.03% |
| S Fund | 9.96% | 8.61% | 33.88% |
| I Fund | 9.11% | 11.12% | 35.03% |
| L Income | 2.95% | 3.21% | 11.62% |
| L 2030 | 5.59% | 5.00% | 20.47% |
| L 2035 | 6.60% | 5.72% | 22.62% |
| L 2040 | 7.16% | 6.09% | 24.34% |
| L 2045 | 7.64% | 6.42% | 25.83% |
| L 2050 | 8.13% | 6.74% | 27.33% |
| L 2055 | 9.84% | 7.95% | 32.65% |
| L 2060 | 9.84% | 7.94% | 32.65% |
| L 2065 | 9.84% | 7.94% | 32.65% |
| L 2070 | 9.84% | 7.94% | 32.64% |
| L 2075 | 9.84% | 7.94% | N/A |
| Data as of April 30, 2026 | |||
Where Do We Go From Here?
After a month with these high returns, what does the future hold? No one knows, of course, but here are several considerations.
There has not been a resolution in the war (or conflict or tension for politically sensitive readers) with Iran. It is likely that there will be more conflict and continuing concern over tension and unsettling events in the Middle East. Energy prices are also a wildcard and likely to fluctuate significantly.
In short, the stock market is subject to sudden reversals in either direction.
While no one knows what will actually play out in the military or political arena, here is the potential impact on the core TSP stock funds.
C Fund (S&P 500 stocks)
- Outlook: This Fund is the most stable among the core TSP stock funds
- Possible modest gains in value but less likely for explosive growth
- The risk for this Fund is price compression if interest rates stay high
S Fund (smaller companies)
- Outlook: Likely the most fragile fund
- These companies need lower rates to keep outperforming
- Possibility of losing ground if economic and financial conditions tighten
I Fund (international stocks)
- Outlook: Mixed results but improving
- This Fund benefits from global recovery and a weaker American dollar
- This Fund is more sensitive to geopolitical shocks
TSP Summary
We wish all readers the best in achieving a comfortable retirement with their TSP investments. The biggest risks for the Thrift Savings Plan Funds now are:
- Interest rates staying high
- Earnings failing to exceed expectations
- A return of geopolitical stress in the Middle East and unpredictable events
