The reliable government securities (G) fund performed the best, but increased just 0.42 percent. Its gains over the previous year remained lower than those for any of the others, with an increase of 4.90 percent.
The stocks from Europe, Australia and some countries in Asia that make up the international (I) fund also had small gains, with a 0.20 percent return. This offering is at the opposite end of the spectrum from the G Fund for longer-term growth, however, outperforming all the other options with 12-month returns of 27.18 percent.
The F Fund, made up of fixed-income bonds, had the smallest losses of the remaining three, losing 0.27 percent for June. Its yearlong earnings remained positive, at 6.23 percent.
The S Fund, which invests in the stocks of small- and mid-sized American companies, lost 1.53 percent, after posting the biggest gains for May. The fund still grew 19.47 percent for the last 12 months.
Finally, the C Fund, which tracks Standard & Poor's 500 Index of stocks in large and medium-sized domestic companies, lost 1.70 percent. But the fund's 12-month gains were the second-highest, at 20.63 percent.
The life cycle or L fund options lost ground for June as well, with one exception. The L Income fund, designed for employees anticipating retirement in the very near future, gained 0.08 percent for the month, and 8.37 percent in the last 12 months. That fund is invested in a conservative mix of stocks, as the life cycle offerings automatically shift money to less risky allocations the closer participants get to retirement.
The other life cycle options had progressively higher losses last month the farther away the target retirement date was. The L 2040 fund lost 0.92 percent; the L 2030, 0.80 percent; the L 2020, 0.54 percent; and the L 2010, 0.20 percent.
The reverse was true of 12-month gains, with long-term returns increasing the farther away the planned retirement. The L 2040 grew 19.49 percent over the year; the L 2030, 17.60 percent; the L 2020, 15.90 percent; and the L 2010, 12.15 percent.