BEIJING, March 14 (Xinhua) -- China's yuan funds outstanding for foreign exchange edged down in February, according to central bank data.

The funds stood at 21.2541 trillion yuan (about 3.17 trillion U.S. dollars) at the end of last month, slightly down by 330 million yuan from that of January, the People's Bank of China said Thursday.

As the Chinese yuan is not freely convertible under the capital account, the central bank has to purchase foreign currency generated by a trade surplus and foreign investment in the country, adding funds to the money market.

Such funds are an important indicator of cross-border foreign capital flows and domestic yuan liquidity.

A similar measure of capital flow, the foreign exchange reserves reported a marginal increase to 3.0902 trillion U.S. dollars at the end of February.