BEIJING, Dec. 28 (Xinhua) -- China's central bank skipped open market operations for the fifth trading day Thursday, citing sufficient liquidity in the banking system.

"Rising fiscal expenditure near year-end is sufficient to offset factors such as maturing reverse repos and keep the banking system liquidity at a high level," the People's Bank of China (PBOC) said on its website.

Some 30 billion yuan (about 4.6 billion U.S. dollars) of reverse repos matured Thursday, meaning that market liquidity will drop by the same amount. A total of 320 billion yuan of liquidity have been drained from the market in the last five trading days.

A reverse repo is a process by which the central bank purchases securities from commercial banks through bidding, with an agreement to sell them back in the future.

The PBOC said earlier that it would conduct open market operations in a flexible way to meet the seasonal liquidity needs of banks near year-end.

China has decided to maintain a prudent and neutral monetary policy in 2018 as the world's second-largest economy strives to balance growth and risk prevention.

"Prudent monetary policy should be kept neutral, the floodgates of monetary supply should be controlled, and credit and social financing should see reasonable growth," said a statement released last week after the Central Economic Work Conference.