Wal-Mart is in aggressive-growth mode in South Florida, opening new stores and adding groceries to existing locations as it looks to win over food shoppers with its everyday-low-price model, according to the Sun-Sentinel. Meanwhile, regional grocery chain Publix, which has 52.8 percent of the market share in South Florida, is fighting back by sticking to its own model of 10-for-$10 deals, BOGO offers and accepting rivals' coupons. Both chains are spending on billboards and radio and TV campaigns to tout their deals.