China Huishan Dairy collapsed 91 per cent in late morning trade before paring back marginally and heading into the break 85 per cent down at HK$0.42.
Trading in the shares was suspended by the start of the afternoon session.
It was not initially clear what caused the sudden sell-off but Bloomberg News reported that hedge fund Muddy Waters had said in December the firm was "worth close to zero" and raised questions about its profitability.
The dairy at the time called for a brief trading halt but dismissed the claims as groundless. It also said chairman Yang Kai had even built on his holdings in the firm, according to the Financial Times.
Until Friday, Huishan had enjoyed a relatively stable performance since its 2013 listing.
Huishan has been contacted for a comment.