A co-founder of SenseTime Group Inc lost almost half of his fortune after shares of the artificial intelligence giant plummeted as much as 51% on June 30.

Tang Xiao’ou, a Massachusetts Institute of Technology graduate and information engineering professor at the Chinese University of Hong Kong, has a 21% stake in the company. His net worth plunged by about US$2.3bil to US$2.9bil , based on the intraday share price, dropping him off a list of the world’s 500 richest people, according to the Bloomberg Billionaires Index.

The fall of SenseTime occurred after the lock-up period on a portion of shares held by cornerstone investors and stakeholders expired a day earlier. Some executives, including chief executive officer Xu Li, pledged to extend the lock-up of their shares until Dec 29.

The tech company completed a Hong Kong listing in December despite US sanctions, and surged as much as 23% on debut. Thursday’s slump dragged the stock below the initial public offering price for the first time.

SenseTime’s technology has been deployed in a range of areas, including assisting police in China, providing product placements in films and creating an augmented reality scene in a mobile game by Tencent Holdings Ltd.

SenseTime reported revenue of 4.7bil yuan and a loss of 6.9bil yuan last year.

 - Bloomberg