OTTAWA (AFP) - US candy maker Hershey on Friday pleaded guilty to participating in a chocolate price-fixing scheme and paid a C$4 million (S$4.9 million) fine.

The company entered the plea at the Ontario Superior Court and, according to the Competition Bureau of Canada, received lenient treatment in exchange for its cooperation in an antitrust investigation.

Earlier this month, Canadian authorities also charged Nestle, Mars and a network of independent wholesale distributors in the case after a whistle-blower tipped authorities to the scheme.

Three individuals were also charged: Robert Leonidas, former president of Nestle Canada; Sandra Martinez, former president of Confectionery for Nestle Canada; and David Glenn Stevens, head of Canadian food distributor ITWAL.

The alleged price-fixing involved chocolate bars sold across Canada from 2002 to 2008, including popular brands such as Kit Kat, Coffee Crisp, Aero, Twix, Snickers, Bounty and M&Ms.

Hershey said previously that the scheme was limited to the Canadian marketplace, and involved, in 2007, executives that were no longer with the Pennsylvania-based company.

Mars, Nestle and ITWAL have vowed to "vigorously defend" themselves against the charges.