BEIJING -- China's appetite for foreign currency increased in September, leading to a widening deficit in foreign exchange transactions among banks, the country's top foreign exchange regulator said Thursday.

Chinese institutions and individuals bought $179.3 billion in foreign currency and sold $163 billion in exchange for 1.1 trillion yuan in September, according to data from the State Administration of Foreign Exchange (SAFE).

As a result, the banks' forex transaction deficit more than doubled to $16.3 billion from that in August, when Chinese banks posted their first monthly net foreign exchange purchase in 13 months.

In the first nine months, Chinese sold $1.43 trillion of foreign currency in exchange for 8.78 trillion yuan while buying $1.25 trillion in foreign currency, resulting in net foreign exchange sales of $172.3 billion.

The fluctuation in forex transactions contributed to changes in China's foreign reserves.

BOC announces yuan bond listing on Euronext	China Development Bank issues yuan bondsin London