A clerk checks U.S. banknotes. [File photo]

U.S. public debt to China jumped US$ 5.2 billion yuan in May, marking its second consecutive monthly increase since April, the U.S. Treasury Department said in a statement yesterday on July 17.

With May's addition, China expands its holdings of U.S. debt to nearly US$1.17 trillion and remains the top creditor of the world's wealthiest nation by gross domestic product (GDP).

Chinese-owned U.S. debt rose US$20.4 billion in April after a two-month decline since February this year.

Japan's holdings of US debt increased US$15.4 billion in May, with the country's reserve hitting US$1.1 trillion, making the island nation the U.S.'s second largest creditor.

The 12 members from the Organization of the Petroleum Exporting Countries (OPEC) took third position by increasing their holdings from US$257.1 billion in April to US$260.9 billion in May.

According to the World Gold Council, China's gold reserves ranked sixth in the world in May at 1,054.1 tons, which account for only 1.6 percent of its foreign exchange reserves. The low ratio has triggered wide speculation that China is attempting to increase its U.S. debt holdings in a shrinking gold reserves pool.