U.S. caught China buying more debt than disclosed

``By the beginning of 2009, China, which uses multiple firms to buy U.S. Treasuries, was regularly doing deals that had the effect of hiding billions of dollars of purchases in each auction, according to interviews with traders at primary dealers and documents viewed by Reuters... The practice kept the true size of China's holdings hidden from U.S. view, according to Treasury dealers interviewed, and may have allowed China at times to buy controlling stakes - more than 35 percent - in some of the securities the Treasury issued.''