Release: U.S. Treasury-Owned Gold
The Status Report of U.S. Government Gold Reserve can be found on FiscalData and is available for download in multiple machine-readable formats with complete metadata.
Book value is determined such that the Department of the Treasury records U.S. Government owned gold reserve at the values stated in 31 USC § 5116-5117 (statutory rate).
U.S. Department of the Treasury. Fiscal Service, Book Value of Federal Reserve Bank Held Gold Coins On Display [FRDGCSV], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/FRDGCSV, April 15, 2021.