Equities slumped on Monday as investors cashed out to lock in gains from October's bullish market and a batch of listed companies delayed the release of their third quarter earnings reports, said experts.

The Shanghai Composite Index fell by as much as 1.7 percent on Monday morning and closed the day with a 0.77 percent decline to 3,390.34 points. The Shenzhen Component Index dropped by 1.15 percent, and the ChiNext startup index tumbled 2.12 percent.

Chinese liquor producer Kweichow Moutai Co Ltd dropped by 4.24 percent on Monday after shares rose to a record high last Friday. Shares of more than 30 listed companies fell by the 10 percent downside limit on Monday.

"The A-share market was very bullish in October, and investors felt the need to cash out and lock in gains," said Dong Dengxin, a finance professor at Wuhan University of Science and Technology.

The Shanghai Composite Index had on Friday increased by 1.26 percent compared with that on Oct 9, the first trading day of October. The Shenzhen Component Index rose 1.6 percent and the ChiNext startup index by 0.34 percent.

Dong said investors were sensitive about the Shanghai Composite Index breaching the 3,400 point mark, and many of them preferred to adopt a wait and see attitude.

Hong Hao, chief strategist at BOCOM International, said another negative factor for Monday's slump was that many listed companies delayed the release of their third quarter financial reports.

About 17 listed companies had delayed release of their third quarter financial reports by Oct 25, whereas the number during the same period last year was only five, data from information service provider Wind showed.

Wind data also showed that at least 596 listed companies will release their earnings statements on Oct 31, the last day allowed for the third quarter reports.

China's Hushen 300 index futures closed lower on Monday, with the contract for November 2017 down 0.68 percent to finish at 3,981.6 points. The December 2017 contract lost 0.69 percent to close at 3,976.6 points. The March 2018 contract was down 0.63 percent to finish at 3,980 points. The June 2018 contract went down 0.66 percent to finish at 3,975 points.

The stock-index contracts, agreements to buy or sell the Hushen 300 Index at a preset value on an agreed date, are designed to allow investors to bet on and profit from either gains or declines in the market.

Xinhua contributed to the story.