Japan, China, UK and hedge funds(?)

...are the largest holders of US Treasury debt, in order of holdings. Note Japan still dominates all others.

Is it plausible that hedge funds hold $100B in US Treasury debt? A recent JP Morgan report concludes that hedge funds currently account for $900B in capital, out of a world total capitalization of $74 Trillion in equity and fixed income. So, the notes held by secretive Caribbean entities account for only 10% of hedge fund capital.