Including their brandname chains:
- Atlantic Cash & Carry
- Atlantic Superstore
- Axep
- Bloor Street Market
- Dominion
- Les Entrepôts Presto
- Extra Foods
- Fortinos
- Freshmart
- L’Intermarché
- Loblaws / Loblaw GreatFood / Loblaws CityMarket
- Lucky Dollar Foods
- Maxi / Maxi & Cie
- NG Cash & Carry
- No Frills
- Provigo
- Real Canadian Superstore
- Shop Easy Foods
- Shoppers Drug Mart / Pharmaprix
- SuperValu
- T & T Supermarket
- Valu-mart
- Wholesale Club / Club Entrepôt
- Your Independent Grocer / Independent CityMarket
- Zehrs Markets
Yes there are other big oligopoly chains like metro, Sobeys/Safeway, Pattison, but I think it’s best to start with one major chain to see how much coordinated action can affect them.
None of the grocery stores or drug stores in my town are associated with Loblaws and the one grocery store on my way home from work is Costco, so I already don’t shop at Loblaws 99%+ of the time.
However if I’m out and about I’m not going out of my way to avoid it.