The I Fund was virtually flat in June, losing 0.03%. Narmeen Arshad/Getty Images

The federal government’s 401(k)-style retirement savings program posted mixed results in June, ending two straight months of consistent growth.

The Thrift Savings Plan’s S Fund, which is made up of small- and mid-size businesses, saw the best performance, gaining 4.34% last month. Since January, the S Fund has grown 18.41%.

The fixed income (F) fund increased 0.25% last month, bringing its 2026 performance to 0.74%. And the G Fund, which is made up of government securities, increased by its statutorily mandated rate of 0.37%. So far this year, the G Fund has swelled 2.18%.

But the I Fund was virtually flat in June, losing 0.03%. That brings the I Fund’s 2026 performance to 16.53%. And the C Fund’s common stocks fell 0.95%, bringing its gains since January down to 10.20%.

Each of the TSP’s lifecycle (L) funds, which shift toward more conservative investments as participants approach retirement age, posted muted gains in June. The L Income Fund, designed for those already making withdrawals, gained 0.30%; L 2030, 0.21%; L 2035, 0.18%; L 2040, 0.16%; L 2045, 0.14%; L 2050, 0.12%; L 2055, 0.06%; L 2060, 0.06%; L 2065, 0.06%; L 2070, 0.06%; and L 2075, 0.06%.

Since January, the L Income Fund has grown 5.24%; L 2030, 8.33%; L 2035, 9.55%: L 2040, 10.21%; L 2045, 10.77%; L 2050, 11.34%; L 2055, 13.41%; L 2060, 13.40%; L 2065, 13.40%; L 2070, 13.40%.