The head of the world's largest online gaming company was charged alongside others Wednesday with insider trading and stock manipulation, authorities in Canada's Quebec province where Amaya is headquartered announced.

Among the allegations are that Amaya chair and chief executive David Baazov "used privileged information pertaining to the securities of Amaya Inc. for trading purposes" between December 2013 and June 2014, around the time the company bought Oldford Group, the world's largest poker business and owner and operator of sites PokerStars and Full Tilt Poker, for $4.9 billion.

The two sites have nearly 100 million registered players on desktop and mobile devices, according to Amaya.

Baazov faces five charges in total, including communicating privileged information and attempting to influence stock market prices.

In a statement he denied the accusations.

Quebec's Autorité des marchés financiers (AMF) said it has ordered Baazov and 12 others who allegedly made Can$1.5 million trading in different securities while in possession of privileged information from 2011 and 2016 to cease all trading.

Several companies they control were also targeted in the investigation.

Authorities made no allegation of wrongdoing by Amaya or any of its subsidiaries or other directors or officers.

Its stock price, however, plunged more than 20 percent in morning trading (1500 GMT) Wednesday in Toronto to Can$14.63.

The company's board said in a statement it is backing Baazov, who only two months ago signalled his intention to buy back Amaya shares and take it private.