Most TSP funds tumbled in March

Nearly all the portfolios within the federal government’s 401(k)-style retirement savings program lost ground last month, as the global economy buckles from disruptions resulting from President Trump’s bombing campaign in Iran.

The Thrift Savings Plan’s G Fund, which is made up of government securities, was the sole offering to finish March in the black, increasing by its statutorily mandated rate of 0.34%. So far in 2026, the G Fund has gained 1.04%.

The common stocks of the C Fund lost 4.98% last month, bringing its performance since January to 4.34% in the red. And the small- and mid-size businesses of the S Fund fell 4.58%, wiping out its gains this year. So far in 2026, the S Fund has lost 1.22% in value.

The I Fund, which is made up of international investments, was hardest hit in March, finishing the month 9.35% in the red. So far this year, the I Fund has gained 1.84%.

And the fixed income (F) fund lost 1.77% last month, bringing its 2026 gains down to 0.04%.

Likewise, each of the TSP’s lifecycle (L) funds, which shift toward more conservative investments as participants get closer to retirement, lost value in March. The L Income Fund, designed for people who have already begun making withdrawals, fell 1.66%; L 2030, 3.67%; L 2035, 4.29%; L 2040, 4.69%; L 2045, 5.04%; L 2050, 5.37%; L 2055, 6.40%; L 2060, 6.40%; L 2065, 6.40%; L 2070, 6.40%; and L 2075, 6.40%.

Since January, the L Income Fund has grown 0.26%, the sole L fund still in the black for 2026. The L 2030 Fund lost 0.56%; L 2035, 0.82%; L 2040, 0.99%; L 2045, 1.14%; L 2050, 1.29%; L 2055, 1.73%; L 2060, 1.73%; L 2065, 1.73%; L 2070, 1.73%; and L 2075, 1.73%.