Authorities in Canada have charged the food giants Nestle and Mars, together with a network of independent wholesale distributors, in an alleged conspiracy to fix prices of chocolates.
The Competition Bureau in the capital Ottawa said it has uncovered "evidence" suggesting price-fixing.
Nestle Canada, Mars Canada, and the distributors ITWAL have been charged.
The Bureau said the Canadian division of the US confectionery company Hershey co-operated with its investigation.
Officials said Hershey Canada, an alleged co-conspirator, is expected to plead guilty at a hearing later this month in exchange for leniency.
"We are fully committed to pursuing those who engage in egregious anti-competitive behaviour that harms Canadian consumers," said John Pecman, Interim Commissioner of Competition.
"Price-fixing is a serious criminal offence and today's charges demonstrate the Competition Bureau's resolve to stop cartel activity in Canada," he added.
Three individuals have also been charged as part of the investigation.
They are former Nestle Canada president Robert Leonidas; Sandra Martinez, former president of confectionery for Nestle Canada; and David Glenn Stevens, president and chief executive of ITWAL.
Mars, Nestle and ATWAL vowed to fight the charges
Mars Canada said in a statement: "Mars Canada intends to vigorously defend itself against these allegations.
"It is Mars Canada's policy not to comment on pending litigation and we are therefore unable to make any additional comments in relation to this matter, which is now before the court."
But Hershey said it would plead guilty to one count of price fixing, dating from 2007, blaming previous management.
"The current Hershey Canada senior management team as well as the Hershey company and its management had no involvement in this conduct," it said.