Market share data has indicated that the retailer's resurgent sales performance in recent months may be coming to an end. Research from Nielsen suggested Sainsbury's suffered the lowest sales increase among the big four chains in the three months to October 31, with market share growth also easing as Tesco returns to form. Sainsbury's had emerged as a surprise winner in the recession as it tempted shoppers away from Tesco and more expensive grocers, led by successful advertising campaigns such as Feed your Family for a Fiver.