Sainsbury’s sales for the 12 weeks to 23 April were up 0.2% year-on-year to £4.26bn, while Asda’s grew 1.4% to £4.16bn, according to Kantar Worldpanel data.
Both were behind the market’s growth rate of 2%, however, while Tesco and Morrisons grew slightly faster at 2.1% and 2.2% respectively.
The combined market share of the two supermarkets, according to Kantar, is 31.4%, down from 31.8% for the same period last year. Tesco’s market share was flat at 27.6%.
Aldi and Lidl grew sales at 7.7% and 9.1% respectively. They now have a combined market share of 12.7% – up from 11.9% a year ago.
This was a strategy supported by the shoppers and sales of the two brands, Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel, said.
"Sainsbury’s appeals to more affluent shoppers (ABC1)," he said. "This demographic accounted for 62% of all sales at Sainsbury’s in comparison to 46% of sales at Asda.
"Meanwhile, Sainsbury’s premium own-label line ‘Taste the Difference’ clocked up sales of £832m annually – nearly two and a half times the size of Asda’s ‘Extra Special’ range."