Shares in several Hong Kong-listed companies fell more than 70% suddenly on Thursday.

Investors and analysts are baffled as to what caused the sudden plunge.

Jiayuan, a property developer, was the worst impacted by the crash, dropping as much as 81%, and seeing more than $HKD25 billion ($3.2 billion) wiped from its market capitalization in a single afternoon.

The stock price of several Hong Kong-listed companies plunged during trading Thursday, leaving investors and analysts baffled as to what caused the sudden plunge.

Among the worst hit companies were Jiayuan International Group, Sunshine 100 China Holdings, and Rentian Technology Holdings, all of which saw their share prices drop more than 70% during the worst of the plunge. More than 10 companies saw their shares drop more than 20% during afternoon trading on Thursday.

Jiayuan, a property developer, was the worst impacted by the crash, dropping as much as 81%, and seeing more than $HKD25 billion ($3.2 billion) wiped from its market capitalization in a single afternoon. The total value wiped off Hong Kong's market was around $HKD37 billion ($4.7 billion).

Investing.com

Analysts so far have been at a loss to explain the sudden crash, which started between 2.00 p.m. and 3.00 p.m. Hong Kong time (1.00 a.m. to 2.00 a.m. EST).

Read more: The downtrodden pound could be a big winner from the UK's Brexit chaos, but investors are expecting a bumpy ride

"No one really knows what’s going on here," Castor Pang, head of research at Core Pacific-Yamaichi International told Bloomberg. "For common investors, it’s a very surprising and tough situation as there was no time to get out."

Some analysts tentatively suggested that the crash in Jiayuan, which is the 32nd largest company listed in Hong Kong by market capitalization, may have been caused by worries that the company may default on upcoming debt payments.

"There is worry that they will not be able to repay the bonds, which triggered fears over default," Louis Wong Wai-kit, director of Phillip Capital Management told the South China Morning Post.

Another analyst, Kenny Tang Sing-hing, chief executive of China Hong Kong Capital Asset Management, said that the crash may have been down to worries about "the liquidity situation among mainland Chinese property stocks."