ASDA has seen its share of the supermarket sector here drop by 0.7% to 17%, new research has revealed.
And it is the only multiple on the list to suffer a decrease in the size of its share in the last year, according to the Kantar Worldpanel Supermarket Market Share report.
The chain, which has 17 stores around Northern Ireland, is part of US giant Wal-Mart.
Meanwhile budget retailer, Lidl, which has 38 stores here, showed the strongest results of all of NI's multiple retailers with an increase in its share of the market of 5.7%.
This now means that the German discounter holds a share of 5.4% in Northern Ireland.
"Together, Lidl and Asda have seen a mixed bag of results this year," said David Berry, director at Kantar Worldpanel.
"Though Lidl has experienced impressive sales growth of 5.7% - with the average basket growing by £1 - Asda has seen sales fall back by 0.7% as shoppers spend £24 less than the previous year.
"Lidl's growth is holding pretty steady, with sales up 5% in December and 6% in November." JP Scally, Lidl Northern Ireland managing director, welcomed the latest supermarket figures.
"Lidl Northern Ireland has had a fantastic 2017 and this was capped by our strongest Christmas trading period to date since entering the market in 1999.
"Our 800-strong team shipped, packed and scanned millions of items for our ever increasing customer base, delivering quality products at exceptional prices."
And he said the outlook for this year is "very positive". "...A number of construction projects will future-proof our business and provide much needed support for our growing store network.
"Lidl Magherafelt will be replaced by a new concept store at the end of February which will boast a brand new architectural design and spacious layout incorporating wider aisles, as well as modern staff and customer facilities."
Tesco, which has around 50 stores here, continues to hold on to its number one position in the supermarket charts with a 35.2% share of the sector, up 3% on last year.
Overall, growth across the big four was relatively consistent with trends in recent years, with the exception of Asda's drop. Mr Berry said Tesco's continued growth is driven by shoppers' spend.
"Inflation now stands at 3.8%, its highest level since March 2014, with the total market experiencing growth of 1.6%. The key to Tesco's success is an increase in shopper spending: customers have spent an additional £73 in the supermarket, making an extra two trips on average throughout the year," he said.
However it is expected that the Consumer Prices Index (CPI) will reveal today that inflation fell to 3% in December.
In the independent sector, the symbol groups suffered a drop in share of 3.4%, holding 8.2% of the market.