15. Canada For the first time in recent history, Canada's holdings of US debt has broken into the top 15, surpassing Taiwan by about $3.6 billion in November 2010. Canada's holdings of US debt in 2010 have increased in each of the past 12 months, shooting up 266% since November 2009. 14. Hong Kong US debt holdings: $138.9 billion Hong Kong is one of the world's largest holders of US debt, although in 2010 the region has cut its holdings by approximately $8 billion from January levels. 13. Caribbean Banking Centers US debt holdings: $146.3 billion The US Treasury identifies this group as institutions in the Bahamas, Bermuda, the Cayman Islands, Netherlands Antilles, Panama and the British Virgin Islands. Holdings are currently listed at $146.3 billion, down about $20 billion from 2010's high of $166.3 billion in May 2010. The group's all-time high of $213.6 billion was reached in March 2009. 12. Brazil US debt holdings: $184.4 billion The South American economic giant has $184.4 billion in holdings, according to the Treasury. Brazilâs investment into US debt has been fluctuating slightly over the past two years, but this current level respresents an all-time high for the country. 11. Oil Exporters US debt holdings: $210.4 billion Big oil means big money... and big investment into US debt. Included in the group of oil exporters are Ecuador, Venezuela, Indonesia, Bahrain, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, the United Arab Emirates, Algeria, Gabon, Libya, and Nigeria. The group combines for a total of $210.4 billion, which is within the $190 billion to $232 billion range they have maintained in the past year. 10. Insurance Companies US debt holdings: $261.8 billion According to the Federal Reserve Board of Governors, insurance companies hold $261.8 billion in Treasury securities. This group includes property-casualty and life insurance firms. 9. Depository Institutions US debt holdings: $269.8 billion As of June 2010 (the most recent numbers currently available), the Federal Reserve Board of Governors lists depository institutions as holding approximately $269.8 billion in US debt. This group includes commercial banks, savings banks and credit unions and has nearly tripled from Q4 2008, when holdings stood at $105 billion. 7. (Tied) United Kingdom US debt holdings: $511.8 billion Britain currently holds $511.8 billion in US debt. The country has ramped up its debt throughout 2010, rising from $208.3 billion in January to the most recent November numbers, which have the holdings up approximately 246% during the year. 7. (Tied) State and Local Governments US debt holdings: $511.8 billion US state and local governments have over a half-trillion dollars invested in American debt, according to the Federal Reserve. That's the same amount of US debt held by the United Kingdom. The level of investment has remained very stable over the past three years, moving within the range of $534.7 billion and $550.3 billion from 2006 to 2009, and although the amount has been increasing, the total value of holdings are off the highs. However, this number does not include an additional $174.5 billion of holdings of treasury notes in state and local government pension funds. 6. Mutual Funds US debt holdings: $637.7 billion According to the Federal Reserve, mutual funds hold the fifth largest amount of US debt compared to any other group, although mutual fund holdings have diminished by nearly $130 billion since December 2008. Including money market funds, mutual funds and closed-end funds, this group of investments manages approximately $637.7 billion of US Treasury securities as of June 2010, which are the most recent numbers available. 5. Pension Funds US debt holdings: $706.4 billion Pension funds control large amounts of money, reserved for personal retirements, and thus are obligated to make relatively safe investments. This group includes both private and local government pension funds, totaling $706.4 billion. The private pension fund category also includes US Treasury securities held by the Federal Employees Retirement System Thrift Savings Plan "G Fund." 4. Japan US debt holdings: $877.2 billion A major US trade partner, Japan holds a huge amount of American debt, and has traditionally been one of the US's largest debt holders, currently owning $877.2 billion of treasury securities. 3. China US debt holdings: $895.6 billion The largest foreign holder of US Treasury securities, China currently holds $895.6 billion in American debt, although it is down from all time highs of $929 billion one year earlier in November 2009. 2. Other Investors/Savings Bonds US debt holdings $1.458 trillion With the most recent numbers from Sept 2010, this extremely diverse group includes individuals, government-sponsored enterprises, brokers and dealers, bank personal trusts, estates, savings bonds, corporate and non-corporate businesses for a total of $1.458 trillion. Although the level of debt held in U.S. savings bonds has remained relatively constant since 2000, the broad category of "Other" investors has nearly quadrupled since reaching a four-year low in September 2007. 1. Federal Reserve and Intragovernmental Holdings US debt holdings: $5.351 trillion Thatâs right, the biggest holder of US government debt is actually within the United States. The Federal Reserve system of banks and other US intragovernmental holdings account for a stunning $5.351 trillion in US Treasury debt. This is the most recent number available (Sept 2010), and marks an all-time high. About a decade ago, the total government holdings were "only" $2.5 trillion.