China markets slump to 5-year lows as regulator promises to protect small investors

BANGKOK — Chinese shares gyrated on Monday, sinking to 5-year lows after market regulators sought to reassure jittery investors with a promise to crack down on stock price manipulation and “malicious short selling.”

Shares in Shanghai and the smaller market in Shenzhen, near Hong Kong, swung between big losses and small gains throughout the day. The markets have languished on heavy selling of property shares, which are enduring a slump in the real estate market.

The China Securities Regulatory Commission held a meeting Sunday focused on stabilizing the markets, state-run Chinese media reported. A notice on its website appeared designed to reassure individual investors who account for more than half of trading volume.

It vowed to crack down with harsh punishment for insider trading and other violations.

“We must sincerely listen to the voices of the broad numbers of investors,…