China's foreign-exchange reserves rose to a six-month high at the end of December, as the yuan rebounded against the U.S. dollar, official data showed.

People's Bank of China said the country's hoard of foreign exchange increased $12.3 billion from a month earlier to $3.108 trillion in December, reversing a $9.6 billion drop in November. December's increase was slightly smaller than a median forecast for a $14 billion rise.

The U.S. dollar index fell due to global trade conditions, major central banks' policy moves and the U.K. election, offsetting some effects from weaker bond prices, the State Administration of Foreign Exchange said in a statement after the data was released.