Asda claims to have ‘pretty significant war chest’ but analyst says it is unclear if it can commit to months of cuts

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More than £4bn has been wiped off the value of Tesco, Sainsbury’s and Marks & Spencer stock since Friday amid fears that rival Asda will step up the grocery price war.

Tesco, the UK’s biggest supermarket, took the biggest hit as its share price fell more than 12% on Monday, while second-place Sainsbury’s was down more than 8%, with M&S dropping 9%.