After rattling the U.S. earlier this year by advocating a new key currency that could replace the mighty U.S. dollar, China has returned to rally behind the greenback. At the recent G8 summit China took a step back from pushing for a replacement currency, saying the issue was not Beijing's official stance. New data also shows China acquired an enormous amount of U.S. government notes and bonds in May. The state-run China Daily newspaper reported on Sunday that China's holdings of U.S. Treasuries totaled US$801.5 billion as of the end of May, up $38 billion from April and the first time the total has exceeded $800 billion. The monthly increase was also the largest since $65.9 billion in October of last year.

Since the global financial crisis erupted in the second half of last year, China has been gradually reducing its purchasing of U.S. Treasuries. Last April saw the first time in 11 months that its total holdings of U.S. Treasuries actually declined compared to the previous month, falling $4.4 billion.

Experts say China has renewed its interest in U.S. Treasuries because it is difficult to find a replacement for the dollar and more attractive investments are still hard to come by. Another factor is apparent signs of recovery in the U.S. economy.

China's foreign exchange reserves rose only $7.7 billion during the first quarter, but in the second quarter they leaped by $177.9 billion. The total amount now stands at $2.13 trillion. As China's economic recovery becomes more evident, foreign investors are flocking to the Asian country. But for China, nothing offers the scale and security of the  U.S. Treasury. Investing in natural resources in other countries or acquiring foreign businesses are mid to long-term investments and are not effective in resolving the problem of excess dollars over the short-term.

"Although the U.S. dollar is showing signs of fatigue, it is difficult over the short-term to find a channel of investment as stable as the U.S. Treasury market," Ding Zhijie, a professor at China's University of International Business and Economics, said in an interview with state-run Xinhua News Agency. Yang Pyoung-seob, head of the Beijing office of the Korea Institute for International Economic Policy, said, "Another factor that appears to have played a role is the relatively faster rate of recovery of the U.S. economy compared to Europe and Japan." Yang added, "China's foreign exchange reserves have surged, so Beijing's purchases of U.S. Treasuries should continue."

At the same time, calls within China to replace the dollar as the key currency have abated. The reasoning seems to be that the value of China's dollar holdings may decline if Beijing joins the "anti-dollar" camp, which was formed by the European Union, Russia and India following the G20 global financial summit in April.

China's Vice Minister of Foreign Affairs He Yafei, who accompanied President Hu Jin-tao to the G8 summit, met with reporters in Italy on July 5 and said the dollar "will maintain its position as the key currency for years to come." Calls to create a new super-currency are "not the official position of the Chinese government," he added. One diplomatic source in China said, "The Chinese government, which sought to rattle the dollar's prominence, has rejoined the 'dollar bloc' that includes Japan and the U.S." The decision, the official added, stems from the view that dollar instability is against China's interests.