A Chinese investor reacts as she looks at prices of shares at a stock brokerage house in Huaibei city, East China's Anhui province, February 21, 2013. [Photo/IC]

For many investors, yesterday is "black Monday" because the Shanghai Composite Index sank 260 points to close at 3,116 points. During its swings the lowest point was even 3,095. Comments:

The past bull market almost ran mad and it was finally reined in on Monday with the index falling. We hope China's stock market will grow healthily, so that the index rises because companies make a profit, not because capital speculates.

Liu Shuwei, a finance professor at the Central University of Finance and Economics, Jan 20

The stock market is a place where the rich and powerful deprive the poor of their last penny. That was my warning a month ago when the stock market "flourished" and it proved true yesterday. The domestic stock market is not running on economic rules, but following orders from power; ordinary shareholders, please exit to avoid bigger losses!

Cheng Lingxu, general manager of Xiamen-based Wofeng Software, Jan 20

China's stock market is one of speculation, instead of smart investment; that's the root problem why today might be summer but tomorrow can be winter. A profound reform is needed so that this distortion is curbed.

Cao Fengqi, a professor of financial and securities studies at Peking University, Jan 20