The Federal Trade Commission recently gave clearance to the proposal but the Canadian Competition Bureau has yet to rule on the deal, according to media reports.
The merger also has to wait until shareholders from both companies have voted on the deal.
If all goes ahead without any problems the $6bn company will have established brands in leading markets, to include the UK, the US, Canada, and Brazil.
The Molson Coors Brewing Company will have combined beer sales of 60m hectolitres, making it the fifth largest brewer by volume.
Although it was placed as the third largest brewer in the US, Coors held the spot of number two in the UK with a market share of 21%. Molson is Canada’s leading brewer with a 43% market share.