The answer is illustrated below:

The United States’ total public debt outstanding was approximately $13.562 trillion at the end of the government’s fiscal year on 30 September 2010. As of 4 January 2011, the United States’ total public debt outstanding exceeds 14 trillion dollars.

Despite that near half-billion dollar increase, the percentage composition of who owns the U.S. national debt shown in the chart above is relatively unchanged. On the whole, U.S. individuals and institutions, when including the Social Security, U.S. Civil Service and Military trust funds own 62.2% of the U.S. national debt, while foreign nations own the remaining 37.8%.

Notes

“All Other Foreign Nations” are all those except China (for which we’ve included Hong Kong), Japan, United Kingdom, Brazil and “Oil Exporters.”

“Oil exporters” include Ecuador, Venezuela, Indonesia, Bahrain, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, the United Arab Emirates, Algeria, Gabon, Libya, and Nigeria.

The “U.S. Civil Service Retirement Fund” fund is the Federal Civil Service Retirement and Disability Fund. The “U.S. Military Retirement Fund” is the Department of Defense Retirement Fund. The “Social Security Trust Fund” is the Federal Old-Age Survivors and Disability Insurance Trust Fund.

Data sources:

U.S. Treasury Department. Monthly Statement of the Public Debt of the United States, September 30, 2010.

U.S. Treasury Department. Major Foreign Holders of Treasury Securities. (At end of September 2010).