Hershey has been fined C$4m (US$3.8m) after admitting fixing the price of chocolate products in Canada.

The Reese’s maker has been hit with the penalty after owning up to its role in the collusion, which took place in 2007 and has also led to charges for companies including Nestle and Mars Inc.

It was announced earlier this month Hershey had reached a settlement with Canada’s Competition Bureau, which had recommended the US confectionery giant receive “lenient treatment”.

The Bureau said Hershey had admitted it “conspired, agreed or arranged to fix the price of chocolate confectionery products in Canada” six years ago.

“Hershey further admitted that, in 2007, senior employees acting within the scope of their authority at Hershey communicated with other members of the alleged cartel to exchange competitively sensitive pricing information about chocolate confectionery products in Canada,” the competition watchdog said.

Nestle, Mars and ITWAL, a network of independent wholesale distributors, have been charged with price fixing. Nestle has said it would “vigorously defend” the charges. Mars and ITWAL have reportedly also said they would defend themselves against the charges.

Three individuals – Robert Leonidas, former president of Nestle Canada; Sandra Martinez, former president of Confectionery for Nestle Canada; and David Glenn Stevens, president and CEO of ITWAL – have also been charged.

The accused face the possibility of a fine of up to C$10m and/or imprisonment for a term of up to five years if found guilty.

The Bureau said it became aware of the collusion through its immunity programme, when one company brought it to its attention. The watchdog did not name the company but reports in Canada named Cadbury, which received immunity from prosecution.