Mr. Simpfendorfer and other economists cautioned that if the July pattern endured, it could quickly become a problem for the United States. Surprisingly, so far, China’s central bank has actually emerged as a big winner from the American turmoil. Its bond holdings of government-sponsored enterprises, estimated by credit rating agencies at $340 billion, rose in value by billions of dollars in a single day when the Bush administration made explicit the government guarantee of Fannie Mae and Freddie Mac bonds, causing their interest rate spreads compared to Treasury bonds to narrow by 5 to 35 basis points within hours.
The exact amount of China’s gain cannot be calculated without knowing the maturity and composition of its holdings of these bonds, which Chinese officials have not released, according to specialists in fixed-income securities.
Beijing officials regulate international capital flows so tightly that the central bank dominates China’s overseas investments. It holds more than 90 percent of all Chinese-owned bonds from Fannie Mae and Freddie Mac, for example.
“The average person on the street in China has no channel to invest in the U.S.,” said Jing Ulrich, the chairwoman of China equities at JPMorgan.
But most private investors elsewhere in the region have considerably more freedom to park their assets in whatever country they please, Mr. Lee, of the Hendale Group, said, and they are very interested these days in assets in Asia.