AGG is the ticker symbol to use to track the G fund.
Sorry WW but I don't think that's right? Close though
Government Securities Investments. The "G" Fund is invested in very short-term U.S. Treasury securities (bonds) guaranteed by the federal government. This is equivalent to a high-yield stable value fund, so there is no possibility of a loss of principal, and there is no risk of loss. As set forth by law, the interest paid by this fund is equal to the average rate of return on outstanding Treasury securities with four or more years to maturity. There is no ticker symbol for the G Fund.
Fixed Income Index Investments. The "F" Fund is invested in high quality securities, which track the Lehman Brothers U.S. Aggregate (LBA) bond index. This index represents a diversified group of U.S. government, corporate and mortgage-related securities. It will also perform similarly to the Vanguard Total Bond Market Index Fund (ticker symbol: VBMFX). For tracking purposes, one can either use the Vanguard Total Bond Market Index Fund (ticker symbol: VBMFX)
or the IShares Lehman Bond Index (ticker symbol: AGG). Through the G and F Funds, TSP participants with low risk tolerance can avoid the stock market entirely.
http://www.thrifttrading.com/funds.html