... years 1998 through 2001, the amount of debt held by the public fell by $476 billion, from $3,815 billion to $3,339 billion. As a consequence of the changesin the federal government s financing ... as of September 30, 2000, to $3,072 billion as of September 30, 2004. By law, trust funds have the authority or are required to invest surpluses in federal securities. As a result, the intragovernmental ... balancesprimarily represent the cumulative surplus of funds due to the trust funds’ cumulative annual excess of tax receipts, interest credited, and other collections compared to spending. As shown...