The Co-operative Group publishes half-year results on Thursday as it seeks to show it is on the road to recovery following the worst crisis in its history.
It slumped to a £2.5 billion loss for 2013 after being dragged down by the near-collapse of its banking arm when a £1.5bn hole was found in its balance sheet.
The group said then its supermarkets showed signs of improvement.
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But latest data from Kantar Worldpanel showed its market share slipping to 6.4 per cent for the 12 weeks to August 17, from 6.6 per cent. Sales fell 1.2 per cent.
The group has been labouring under a £1bn-plus debt mountain but moved to ease some of the burden in July when it sold its pharmacy stores for £620 million.
This month it said it was ending 118 years of crop-growing as it sold its farming business to the Wellcome Trust for £249m.
Housebuilder Redrow is expected to reflect the buoyant housing market when it posts its full-year results on Tuesday.
The Flintshire firm will post sales up 40 per cent to £847.5m on the back of strong London demand. Pre-tax earnings will jump 75 per cent to £126.2m.
The firm, led by founder and chairman Steve Morgan, said in an April trading update reservations were up 17 per cent and average selling prices were 16 per cent up than a year ago, at £289,000.
Bus and rail group Go-Ahead is expected to post strong full-year results on Thursday, driven by its rail division.
Analysts at Investec expect the Newcastle firm to post pre-tax profits up 9.4 per cent to £83m, thanks to lower energy costs and better performance by its Southern, Southeastern and London Midland train franchises.
The firm was last week shortlisted to operate the Northern franchise which runs rural and long-distance services between Cheshire, Greater Manchester, Lancashire and Tyne and Wear.
It also made the shortlist for the TransPennine Express route, linking Edinburgh, Glasgow, Newcastle and Leeds.
Go-Ahead said revenues were up between 5 per cent and 7 per cent on its three existing rail routes when it issued a pre-close trading update in June.