Regulators may let China's four biggest state banks become market makers in U.S. dollar trading, paving the way for less currency intervention by central bank. The China Business Post reported that the draft measures for expanding the number of market makers for U.S. dollar trading have been completed, China Radio International reported Tuesday.

The State Administration of Foreign Exchange -- China's top foreign exchange regulator -- will decide when to announce them.

A market maker agrees to act as either a buyer or seller in a financial transaction when no other party can be found.

The People's Bank of China, the central bank, is now China's key market maker in U.S. dollar trading due to tight restrictions on foreign exchange dealings.

The report said China's four biggest banks -- Industrial & Commercial Bank of China, Agricultural Bank of China, China Construction Bank and Bank of China -- would be the first market makers to be approved.