BEIJING -- As the stock market continued to nosedive, China's securities regulator unveiled Thursday new rules to limit big shareholders from selling their stocks.

The China Securities Regulatory Commission asks big shareholders and the management, who each holds more than 5 percent of a company's shares, not to reduce more than 1 percent of the company's shares within three months, a latest regulation notice said.

Those who want to reduce their holdings have to publicize such plans 15 trading days beforehand, it said.

The new rules will take effect on Jan 9, 2016.