The investigations unit of the Competition Commission of India (CCI) has concluded that Anheuser-Busch InBev, Carlsberg and United Breweries colluded to fix beer prices, two people with direct knowledge said.

The CCI launched the investigation after AB InBev told the watchdog it had detected an industry cartel, leading in 2018 to dawn raids at the three brewers’ offices to collect evidence.

The investigation has found that 15-20 executives from the three brewers were involved in discussions of beer prices before they were submitted to the regulators, thereby violating antitrust laws, said the two sources, who declined to be named as the report is not public.

“The evidence seized by the CCI during searches last year was enough to nail the culprits,” said one of the sources.

AB InBev, the world’s largest brewer, whose Indian offerings include Budweiser and Corona, said it would not be appropriate to comment at this time, but said it takes antitrust compliance “very seriously”.

Carlsberg, which sells beer under its own-name brand and also owns Tuborg, declined to comment on Friday, but had previously said it was “committed to complying” with all the relevant laws.

United Breweries, which is part-owned by Heineken and known for its Kingfisher brand, said it was “given to understand” the investigation report had been submitted to the CCI, and would present its case during the commission’s hearing.

The company added that it had made complete disclosures to the CCI’s investigation unit that it would use to “counter any legal presumptions and material impact against” it.

The CCI did not respond to request for comment. Heineken declined to comment.

CCI chairman Ashok Kumar Gupta and other members of the commission are expected to decide on a penalty over the next few months, or dispute the investigation findings which were submitted in August, the sources said. The report will not be made public and its findings have not previously been reported.

The three brewers, who according to IWSR Drinks Market Analysis account for about 85 per cent of the beer consumption in the $7-billion (£5.5 billion) India market, together face a potential fine of around $280 million.

Any company executive found to have fixed prices could also be fined, though AB InBev could escape its share of the fines as it first reported the issue.