Explaining fluctuations in the Thrift Savings Fund daily balance at US treasury

This article examines the G-Fund, which is one of the five funds in the federal government employee retirement Thrift Savings Plan. The G-Fund is held as internal debt by the U.S. Department of Treasury. Our examination shows that the fund balance is exclusively composed of 1-day notes that are redeemed/reissued every business day, generating $55 trillion in annual debt reissuance. We also show that the fund balance drops substantially as resources are transferred to the general fund when the government is constrained by a debt ceiling and returns to pre-constraint levels when the ceiling is expanded/suspended.