Sainsbury has lost its status as Britain's No. 2 supermarket group by market share to takeover target Asda for the first time in four years, industry data showed on Tuesday.
Sainsbury's sales fell 1.8% over the 12 weeks to March 24, reducing its market share to 15.3% from 15.8% in the same period last year, researcher Kantar said.
That meant Asda, the British arm of U.S. retailer Walmart, overtook Sainsbury with a market share of 15.4% as its sales edged up 0.1%, though Sainsbury remained the biggest seller of food and drink of the two.
Sainsbury argues that Kantar under-reads its general merchandise market share. This is because since acquiring Argos in 2016, Sainsbury has streamlined general merchandise ranges in its stores in favour of Argos ranges. However, Argos' sales are not captured by Kantar.
Sainsbury's agreed £7.3 billion takeover of Asda is being considered by Britain's competition regulator.
The Competition and Markets Authority (CMA) said last month its initial view was that the deal should be blocked in the
absence of the sale of a large number of stores, or even one of the brands. A final report is due by 30 April.
"Walmart's subsidiary seems to be holding up much better to the growing Sainsbury's merger uncertainty," said analysts at Jefferies.
Sainsbury shares, down 26% over the last six months, were down 0.9% at 232.5 pence by 0825 GMT, giving it an equity value of £5.1 billion.
Kantar's data also showed Tesco's sales rose 0.5% in the period and it remained the clear market leader with a share of 27.4%. Sales at No.4 player Morrisons fell 0.1%, giving it a market share of 10.3%.
The Big Four
However, all of Britain's big four supermarkets lost market share to German-owned discounters Aldi and Lidl.
Their sales increased 10.6% and 5.8% respectively, giving them a combined market share of 13.6%.
Kantar said overall UK grocery sales grew 1.4% in the period, the slowest rate since March 2018, reflecting a later Easter this year and Mother's Day falling outside the reported period.
The market researcher said grocery inflation was 1.5% over the 12 weeks. Prices are rising fastest in markets such as cola, crisps and chilled deserts, while falling in instant coffee, fresh sausages and nuts.