Dunnes Stores continues to top Ireland's grocery retailer league, while strikes at rival Tesco last month saw its sales dip by 1pc.
According to research group Kantar Worldpanel, Dunnes Stores had a 22.9pc share of Ireland's multi-billion euro grocery market in the period.
It's the first time it has held the top spot for two consecutive months.
It has been battling SuperValu, the chain controlled by Cork-based Musgrave, for pole position over the past year. SuperValu had a 22.6pc share in the latest period.
Following three months of steady growth, Tesco sales dropped by 1pc during the 12 weeks to February 26 as 11 days of staff strikes led to disruption for the retailer, according to Kantar Worldpanel.
Despite the industrial action only affecting eight stores there has been a clear impact on the retailer's performance, said the research group, with its market share falling by 0.9 percentage points to 21.7pc.
The figures measure market share based on the value of sales rather than volume.
David Berry, director at Kantar Worldpanel, said that shoppers at Dunnes are adding more to their baskets during trips to the chain.
"The grocer's 'Shop & Save' initiative is continuing to influence customers, with the average basket featuring an extra one and a half items - an additional €3 per trip and €25m for the retailer in the past 12 weeks," said Mr Berry.
Aldi and Lidl saw sales rising by 5.3pc and 4.1pc respectively in the latest period.
Aldi has a 10.8pc share of the market, while Lidl has 10.6pc. Over the past 12 weeks Aldi managed to attract an additional 20,000 customers into its stores.