28 Apr 2018 --- J Sainsbury and Wal-Mart, the world's biggest supermarket retailer, are in advanced talks about a tie-up that would create ‎a more powerful rival to Tesco, the UK market leader. A merger between the UK’s second and third largest supermarket chains would create a new group with huge shares of the market in food, clothing, household goods and toy retailing that would be more powerful than Tesco.