The woe continued for Britain's big supermarkets on Thursday as it emerged that Asda had had its worst quarterly sales on record.
The supermarket chain's revenue dropped 5.8% over the final three months of 2015, with like-for-like sales 4.7% lower for the year compared to 2014.
Based on these new numbers, Asda had the worst performance of any of the big supermarkets over Christmas, despite a price-cutting drive.
Chief executive Andy Clarke warned that the chain was not expecting a significant upturn any time soon.
"While I am cautiously optimistic that our sales will gradually improve, it won’t happen overnight given that 2016 is likely to be another tough and competitive year for the sector as a whole,” he said.
It comes after retail researchers Kantar Worldpanel said Asda's sales fell 3.8% and its market share dropped back to 16.2% in the 12 weeks to the end of January.
Asda and Morrisons (LON:MRW) have both been hard-hit by the challenge from discounters Aldi and Lidl, who have been muscling in on territory that they previously held.
Morrisons got a boost from the Kantar figures, which showed its sales decline reducing to 2.2%, although its market share fell by 0.3 percentage points to 10.8%.
Meanwhile, its shares were up on Thursday amid speculation that it could become a takeover target for rival Tesco (LON:TSCO) or a consortium led by private equity firm Permira.
Broker Shore Capital highlighted data such as the Kantar figures as suggesting that Asda had been underperforming the British supermarket trade for some time.
It said the chain's sales fall in the 13 weeks to January 1 was "much worse than we anticipated."
Shore analyst Clive Black said the performance was "clearly a disappointment" for Clarke.
He said Shore had a lot of time for Clarke and said he may be leading a team where a lot of its best and most talented players had been transferred to WalMart in the US.
Black added: "Asda needs a more robust and consistent proposition to our minds. If any of the superstore groups needs to be fighting the fight against the limited assortment discounters, then it has to be Asda, not least because it appears to be the current chief victim of their advance."
Meanwhile, US owner Walmart Stores (NYSE:WMT) has cut back its sales expectations for the year as it missed its forecasts in the final quarter of 2015.
The Asda chain owner blamed strengthening currency impacts as well as a hike in its store-closure plans for the sales drop, as well as stalling sales growth in its U.S. business.
Shares were around 4.5% lower in pre-market trading to $66.13, despite the firm upping its dividend by 2% to $2 per share.
In the fourth quarter of last year, sales at Walmart's U.S. stores ticked up 0.6%, marking the sixth straight quarterly gain, but this was lower than market hopes for a rise of around 1%.
Doug McMillon, chief executive, said: “We are seeing momentum in our Walmart U.S. business,” adding that the company was pleased with its “fundamental trends”.
For the quarter, Walmart reported a profit of $4.57bn, or $1.43 per share, down from $4.97bn, or $1.53 a share, a year earlier.
The world’s largest retailer, which reported earnings of $4.57 per share last year, has knocked back its forecasted earnings in 2016 to between $4 and $4.30 a share, adding that sales growth will likely be “relatively flat”.
Previously, it had forecast revenue growth of between 3% and 4%, but a rise in employee wages, improved stock in its stores and the impact of the recently announced store closures will all adversely impact sales.