Supermarket group SuperValu has reported sales of €2.6 billion in 2015 and it said it now has 25% of the total market share.
The retailer, which is owned by Musgraves, said it performed particularly well in the lead up to Christmas, with growth of 4.3% in the last 12 weeks of the year.
There are 221 SuperValu stores across the country, many of which are franchise operations.
The company, which serves 2.6 million customers each week, said it plans to invest €28m in its network this year. It is aiming to open five new stores, which will create 350 new jobs.
SuperValu noted that online shopping was a key sales driver for it last year, with online sales growing by 32% for the last six months of the year and projected to grow over the next 12 months.