TNS's latest figures for grocery spend showed Asda and Morrisons grew market share by 8.8% and 8.2% respectively over the 12 weeks to February 22 compared to the same period last year.
Tesco grew by only 5%, reducing its overall share of the market from 30.8% to 30.3%, its lowest for three years. Sainsbury's grew by 5.7%, causing its share to fall from 16.4% to 16.3%.
TNS said the results proved Asda and Morrisons’ historical low-price positioning was proving attractive to shoppers who had less disposable income. However, Morrisons and Asda were both beaten by Iceland which grew by 13.6%, possibly heralding a comeback for frozen food.
Separately, US electronics chain Best Buy has halted its move to launch in the UK as a result of the current economic climate.
Best Buy was planning to launch a joint venture with Carphone Warehouse this summer, however, the mobile phone specialist told the Financial Times it is waiting for more attractive store locations to become available.
Some analysts have linked the decision to difficult trading conditions in Best Buy’s home market. US sales have been struggling in recent months while in November 550-store chain Circuit City filed for bankruptcy.
Best Buy's decision will be a relief to Currys and PC World owner DSG International, which announced plans yesterday to plough £320m into a store refurbishment programme over the next two years.
DSG is also planning to launch 50 Currys Megastores, a combined version of Currys and PC World. The investment comes as DSG struggles with the downturn. In January it announced a 10% drop in sales for Q4.