As you can see, over roughly the last year China’s holdings have stayed flat, Japan’s have increased slightly, and our friends in the United Kingdom have increased their holdings significantly. The data is updated periodically on the treasury website. This chart is using the latest data released by the treasury on January 18, 2011.

http://www.treasury.gov/resource-center/data-chart-center/tic/Documents/mfh.txt

(The data at the above link changes periodically, but it can always be found there)

(h/t c4p)