China's yuan funds outstanding for foreign exchange have been on the rise for seven straight months, official data showed Wednesday.

The funds climbed to 21.53 trillion yuan (about 3.13 trillion U.S. dollars) at the end of July, up 10.82 billion yuan from a month earlier, according to the People's Bank of China.

As the Chinese currency is not freely convertible under the capital account, the central bank has to purchase foreign currency generated by 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.

As a similar measure of capital flows, China's foreign exchange reserves rose to 3.12 trillion U.S. dollars at the end of July, earlier data showed.

The State Administration of Foreign Exchange said the country continues to witness stable capital flows across borders and a generally balanced forex market, and expects the foreign exchange reserves to maintain the stable trend.