The C Fund, which invests in the S&P 500 Index, posted 1.90 percent this month. It has risen to 20.09 for the last 12 months.
The low-risk, low-reward G fund remained unchanged at 0.20 percent the lowest yearly return of all the TSP funds. The F fund, a fixed-income index investment fund, performed slightly better than the G fund, posting 0.23 percent in January.
The L Income fund ended January at 0.61 percent, while the rest of the lifecycle funds posted even higher results.