Target has opened its first stores in Canada, a highly competitive market where Walmart Canada has been growing its share rapidly. Canada’s “Big Three” traditional chains — Loblaw Cos., Sobeys and Metro — are still Nos. 1, 2 and 3 in market share, respectively, but Walmart Canada may have passed Safeway Canada as the new No. 4, according to SN estimates. Safeway Canada had 2012 sales of about $6.7 billion in 2012.