Now that’s what you call a share price mooove.

Shares in China Huishan Dairy Holdings, a company that was targeted last year by activist hedge fund Muddy Waters, have taken a sudden plunge of more than 90 per cent, making for one of the biggest-ever falls on the Hong Kong Stock Exchange.

The Hong Kong-listed company has now requested a trading halt following a share price slump that wiped off about $4.1bn in market capitalisation and may have meant hefty paper losses for the company’s chairman as well as major investors including the world’s largest pension fund.

Shares had been trading relatively flat until 10.30am local time when they started to dip. The sell-off accelerated rapidly about an hour later, sending shares down as much as 91.1 per cent.

Shares had recovered slightly to be 85 per cent lower at HK$0.42 going into the local lunch break, having closed at HK$2.80 on Thursday.

In mid-December, Muddy Waters, the hedge fund set up by short-seller Carson Block, released a report in which it said it was shorting the stock, questioned the company’s financial health and said it looked to be on the verge of collapse owing to excessive leverage.

China Huishan requested a trading halt from the Hong Kong Stock Exchange following the release of the Muddy Waters note. A few days later, the company exited the halt and responded via a statement to the exchange that the report “has made allegations which are groundless and contains various misrepresentations, malicious and false allegations and obvious factual errors of the Group”.

The company also said at the time its chairman, Yang Kai, had bought more shares in the group through Champ Harvest, a vehicle that is 90 per cent owned by Mr Yang and 10 per cent owned by Ge Kun. Mr Yang and Ms Gun held an interest in shares representing 73.2 per cent of the company’s issued share capital, according to an exchange filing on December 19.

China Huishan counts a number of high profile international investors among its shareholders, according to Bloomberg data. Among the top five are: Blackrock, with a 1.33 per cent stake, Vanguard with 0.97 per cent and Japan’s massive Government Pension Investment Fund – the world’s biggest pension fund – with 0.3 per cent.

Share volume today of 779.4m represents about 5.8 per cent of the total shares on issue, or about one fifth of those shares not associated with Mr Yang.

The company has a market capitalisation (share price permitting) of $729m.

China Huishan has been listed on the HKEx since 2013.

Charts courtesy of Bloomberg