I made the chart below for an assignment on People's Bank of China monetary policy during the financial crisis. The problem is that it got me very confused about the relationship between these interest rates. Why does 1- year Shibor never decrease below the rediscount rate? In the period between 2008/11 and 2009/07 it even clearly copies it.
My second question would be on what happened in 2011. Both of the market rate just seem to shoot up. If the rediscount rate represents the rate at which commercial banks are able to obtain funds from the central bank, why would banks borrow for Shibor?
I wasn't able to find answers anywhere, so a big thank you to anyone who can help.