https://www.tsp.gov/InvestmentFunds/FundsOverview/index.html Fund Management Resources Publications: Summary of the Thrift Savings Plan You Should Know The FRTIB Executive Director currently allocates the selection, purchase, investment, and management of the assets contained in the F, C, S, and I Funds to BlackRock Institutional Trust Company, N.A. G Fund F,C,S, and I Funds L Funds G Fund The G Fund assets are managed internally by the Federal Retirement Thrift Investment Board. The G Fund buys a nonmarketable U.S. Treasury security that is guaranteed by the U.S. Government. This means that the G Fund will not lose money. F,C,S, and I Funds The Federal Retirement Thrift Investment Board currently contracts BlackRock Institutional Trust Company, N.A. (BlackRock) to manage the F, C, S, and I Fund assets. The F and C Fund assets are held in separate accounts . The F, C, S, and I Funds are index funds , each of which is i...