On Tuesday market research group Kantar Worldpanel is set to say that Asda’s sales for the 12 weeks to January 1 were weak compared to rivals Tesco, Sainsbury’s and Morrisons.
Sales at the Bradford-based grocer, which is owned by American retail giant Walmart, tend to fall during the run-up to Christmas, as its normally price conscious customers trade upwards.
Additionally, retail experts believe Kantar will say that Asda’s market share has fallen year-on year.
Analysts at Bernstein forecast a percentage point fall of 0.6 to 15.6 per cent, leaving it with the same market share it had in January, 2003.
Its zenith was in 2012, when it had 17.8 per cent of the market.
Tesco and Morrisons are thought to have put in strong performances in the run-up to and during the festive season.
Although it has suffered falling sales since May, Sainsbury’s is understood to have benefitted from consumers switching to it from its cheaper rivals for higher quality festive foods.
Retail Remedy senior consultant Paul Thomas said: “Asda will have had a shocking Christmas. On the other hand, we expect Tesco to be really strong, with good customer engagement, service and product selection, they seemed to have recovered quicker.
"We think Morrisons also had a strong Christmas, while Sainsbury’s will have done OK, as their stores are set up well.”
Bruno Monteyne, retail analyst at investment group Bernstein, said: “Tesco won Christmas, but Morrisons and Sainsbury’s were also strong.
"Tesco fixed its Christmas offer with consumers now staying rather than trading up to Waitrose or down to Asda.”
Shore Capital head of research Clive Black said: “Collectively the grocers will have done well this Christmas.
"Tesco and Morrisons will be the strongest of the big four, while Co-op and Iceland will have done well.
“Asda is losing market share and is taking steps to turn things around, but it will be among the laggards.”
Despite those steps, Asda is expected to post a 10th consecutive quarter of falling like-for-like sales when it announces its fourth-quarter results next month.
In June Walmart ousted Asda chief executive Andy Clarke and replaced him with the head of its Chinese operations Sean Clarke (no relation), who is cutting the firm’s costs and prices as part of his turnaround plan.
This week will see a number of high street stalwarts put out trading updates, including JD Sports, Majestic Wine, Morrisons, Debenhams, J Sainsbury, Asos and Marks & Spencer.
Associated British Foods’ first-quarter trading update on Thursday will be scrutinised by investors, as like-for-like sales are falling at its previously unstoppable Primark division.
Retail experts believe that Primark had a tough Christmas, because of increased competition on the high street and online.