Performance in the Thrift Savings Plan continues to rebound from last year's lows.

Balances in the federal retirement fund exceeded $234.4 billion last month, a level not seen since May 2008, said Renee Wilder, director of research and strategic planning for the Federal Retirement Thrift Investment Board.

Fueling the growth is high rates of return for TSP's underlying stock funds. Returns in the S Fund, which tracks small- and medium-sized U.S. companies, approached 29 percent for the nine months ending in September. The I Fund, tied to international stocks, was up more than 27 percent so far this year. The C Fund, which tracks large U.S. companies, was up more than 19 percent since January.

"It's been a volatile year, but things seem like they're turning around," said Gregory Long, executive director of the thrift board, during a board meeting Monday.

The plan's 4.2 million participants are taking note. During August, participants transferred nearly $1.5 billion from the government securities-backed G Fund, which has grown just 2 percent so far this year, and divvied the money into the higher-performing stock funds.

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