BEIJING — China's outstanding yuan funds for foreign exchange went up from a month earlier at the end of March, data from the country's central bank showed on April 15.

The funds came in at about 21.3 trillion yuan (about $3.33 trillion) at the end of last month, up 23.2 billion yuan month-on-month, according to the People's Bank of China.

As the Chinese yuan is not freely convertible under the capital account, the central bank must purchase foreign currency generated by a trade surplus and foreign investment in the country, adding funds to the money market. Such funds are a vital indicator of cross-border foreign capital flows and domestic yuan liquidity.

China's forex holdings amounted to $3.188 trillion at the end of March, down $25.8 billion, or 0.8 percent, from the end of February, said the State Administration of Foreign Exchange.