BEIJING — China’s central bank injected 100 billion yuan (about $15.15 billion) into the market via open market operations on Dec 19 to ease liquidity.

The People’s Bank of China (PBOC) conducted the reverse repos after injecting 300 billion yuan in its last operation.

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.

On Dec 19, the PBOC conducted 50 billion yuan of seven-day reverse repos priced to yield 2.5 percent, 30 billion yuan of 14-day contracts to yield 2.65 percent, and 20 billion yuan of 28-day contracts to yield 2.8 percent.

The central bank has increasingly relied on open market operations for liquidity management, rather than cuts in interest rates or reserve requirement ratios.

China set the tone of its 2017 monetary policy as prudent and neutral, keeping appropriate liquidity levels while avoiding excessive liquidity injections.