With approximately 14M customers each week Loblaw Companies commands a whopping 40% of the grocery market in Canada.  That's almost twice that of Sobeys and its affiliated grocers (IGA, FreshCo, etc).  Though the number of locations overseen by both companies is similar, Loblaw's corporately-run Superstore locations (Real Canadian Superstore in central Canada) are almost 3X larger, giving Loblaws the edge when it comes to sheer size. 

Loblaws reinforced its status in the country with the purchase of Shoppers Drug Mart and later  TNT (serving the suburban market in Toronto) .  However Sobeys has been making inroads in big cities with the acquisitions of Pete's Froutique, a controlling stake in Longo's (Toronto, March 16, 2021, $357 million), Farm Boy (26 stores, $800 million, Toronto, September 24, 2018).

Empire Company Limited (TSX: EMP.A) is a Canadian company headquartered in Stellarton, Nova Scotia. Empire's key businesses are food retailing, through wholly-owned subsidiary Sobeys Inc., and related real estate. With approximately $28.4 billion in annual sales and $15.0 billion in assets, Empire and its subsidiaries, franchisees and affiliates employ approximately 127,000 people.