The PBOC typically enters repo agreements every Thursday when three-month bills mature.
On Tuesday, the PBOC sold 51 billion yuan of one-year bills.
Taking into account the 65.5 billion yuan of bills and repurchase agreements that matured this week, the PBOC drained 500 million yuan of liquidity from the money market through its open market operations this week.
In the previous two weeks, the PBOC drained 123 billion yuan from the money market.