Hong Kong's Hang Seng , which is packed with big Chinese companies, followed Shanghai into bear territory in September. There's another factor weighing on Chinese stocks, though. Big Chinese companies often pledge their stock as collateral in return for loans from brokers. That happened in a big way earlier this year, intensifying losses in the market. Up to 15% of Chinese stocks have been pledged in this way, Choyleva estimates.

Source: CNN December 21, 2018 10:30 UTC