HONG KONG – A string of Hong Kong-listed stocks plunged without warning in afternoon trading, in the latest shock losses to sideswipe investors in the world’s fourth-largest equity market.

Jiayuan International Group Ltd., Sunshine 100 China Holdings Ltd. and Rentian Technology Holdings Ltd. fell more than 75 percent in a matter of minutes and at least 10 companies were 20 percent lower by the close, wiping out HK$37.4 billion ($4.8 billion) in market value. Most of that came from Jiayuan, which lost HK$26.3 billion on record volume.

“Some of these companies might have cross-shareholdings in each other and when one of those starts to tumble, it brings down other related stocks,” said Hao Hong, chief strategist with Bocom International Holdings Co.

“It’s likely more similar stock crashes could happen this year. A lot of share pledges in Hong Kong are underwater, and as soon as the positions are liquidated it triggers an avalanche.”

An “Enigma Network” of 50 stocks roiled the city’s markets in 2017, triggering a crash in dozens of interlinked companies weeks after activist David Webb published a report. In November, more than $1.4 billion was wiped from the value of five small-cap stocks as they tumbled.

Hong Kong exchange rules say a controlling shareholder can borrow against stock and not disclose as long as it’s for personal finance reasons rather than loans, guarantees or other forms of support for the company.

An external representative for Jiayuan said the company wouldn’t immediately comment on the moves, while a spokesman for Hong Kong Exchanges & Clearing Ltd. declined to comment. Sunshine 100 couldn’t immediately be reached.

Some traders pointed to the fact that Jiayuan has $350 million in debt due to mature today, according to data compiled by Bloomberg. Another connection: Gu Yunchang is a board member for both Jiayuan and Sunshine 100, according to data compiled by Bloomberg.

Hong Kong-based Jiayuan sold $400 million of bonds in the fourth quarter, which mature in October 2020. Those securities fell 30 cents to a record low of 70 cents on the dollar as of 3:09 p.m. Hong Kong time, according to Bloomberg-ompiled prices.