BEIJING -- China's yuan funds outstanding for foreign exchange increased by 25.12 billion yuan ($3.97 billion) in February month-on-month, the central bank said Friday.

This meant the central bank bought 25.12 billion yuan worth of foreign exchange from commercial banks last month to offset the same amount of foreign exchange inflow, as China's currency, the yuan, is inconvertible under the capital account.

The rise, however, shrank sharply from 140.9 billion yuan registered in January. The total balance of the funds stood at 25.52 trillion yuan as of the end of February, according to the People's Bank of China.

Analysts said the decelerating growth was related to a trade deficit in the month. China notched a trade deficit of $31.48 billion in February, the largest in more than a decade.

It also stems from continuous falls in the foreign direct investment (FDI) the country received. China's FDI dipped 0.9 percent in February from a year ago, falling for the fourth consecutive month.