Morrison's ( LON:MRW ) bidders might not be too impressed with the 6.7% sales decline it notched up, with Sainsbury's ( LON:SBRY ) and Tesco ( LON:TSCO ) comfortably the best of the big four though they still posted falls of 3% and 3.7% respectively. Tesco also achieved its biggest year-on-year market share increase since December 2016, growing from 26.7% last year up to 27.1% in the latest 12 weeks. "Sainsbury's, where online sales continue to perform strongly, moved its share up to 15.2% from 14.9% last year," added Kantar.