CuongNhuka
Senior Master
http://en.wikipedia.org/wiki/United_States_public_debt
If you look at direct foreign ownership of US companies, China is often not even on the map.
http://www.treas.gov/offices/international-affairs/cfius/docs/CFIUS-Annual-Rpt-2008.pdf
You may be thinking of Sovereign Wealth Funds:
http://en.wikipedia.org/wiki/Sovereign_wealth_fund
If you look at the CIC, it becomes more clear.
http://en.wikipedia.org/wiki/China_Investment_Corporation
http://www.eeo.com.cn/ens/finance_investment/2009/03/06/131432.shtml
I remembered my source. It was a teacher from High School, I'll ask him his source (he has graduate degrees in Economics and Politics, so I'm sure he knows what he's talking about).