Analysts predict a price war nastier than anything seen so far as Loblaws tells its suppliers to reduce the price of everything the grocer buys by 1.45 percent. In response, the huge wholesale buyer United Grocers, which buys for Metro and other Loblaws competitors, has told manufacturers that it wants the same cut in prices. The meanness of the atmosphere is revealed by a threat to simply reduce all invoices by that amount if the sellers don’t comply. What’s going on? Many informed business sources say it’s about the ambitions of Walmart and Costco to muscle their way further into the Ontario grocery market. It is said these two mammoths have already made inroads in Quebec, controlling as much as 15 percent of the market.