http://www.cnbc.com/id/29880401/The_Biggest_Holders_of_US_Government_Debt?slide=16
That’s right, the biggest holder of US government debt is actually inside the United States. The Federal Reserve system of banks and other US intragovernmental holdings account for a stunning $5.127 trillion in US Treasury debt. This is the most recent number available (Sept 2009), and is at an all-time high, rising in every reporting period since 2007. About a decade ago, the total government holdings were “only” $2.5 trillion.