Here's the Wall Street Journal on Why China's Market Fell So Much

  1. Further evidence that its economy was slowing (Caixin PMI release Monday)
  2. Beijing was weakening the yuan
  3. Also appeared to be hastened by expectations that support propping up the market could disappear soon (one of the bailout measures imposed by the government during the crash is set to expire on Friday ... big shareholders were banned from selling stock for six months. Most analysts expect Beijing to extend the ban if the market keeps falling.)
  4. As well as the debut of new circuit breakers (traders expected trading to be halted so they sold before it was)

The piece doesn't add any other factors to what Adam posted earlier: Four reasons for the drop in Chinese stocks to start the year (#3 is a new one)