The British grocery market grew at the slowest pace for 11 years during the past 12 weeks, according to data from Kantar Worldpanel.
Tesco suffered a 3.7% drop in like-for-like sales in the three months to 24 May and its market share slumped from 30.5% to 29% – the biggest fall since Kantar’s records started in 1994.
Morrisons’ share dropped from 11.6% to 10.9%, Sainsbury’s grew slightly to 16.7%, while Asda remained at 17.1%.
Discounters Aldi and Lidl continue to grow quickly, boosting their market share to 4.7% and 3.6% respectively.
Waitrose’s strategy to be “everything that the discounters aren’t” has helped keep its record 5.1% stake.
Tesco chief executive Philip Clarke said the acceleration of the retailer’s £200m price-cutting plan had hit short-term sales.
“The first quarter has also seen a continuation of the challenging consumer trends in the UK, reflecting still subdued levels of spending,” he said.