Two out of every three euros spent on food and groceries in the Irish Republic go to the three major players in the sector, Tesco, Dunnes Stores and SuperValu.
That's one of the main findings in a new report on the market, A Supplier's Guide to Trading in Ireland, by IGD.
It estimates the total value of the market last year at E12.7bn, an increase of 5.3% on the 2004 figure, with the annual grocery spend per capita up 3.1% to E3,078. Tesco is not just the market leader, with a 26% share - it also attracts younger shoppers than its competitors.
The report found that almost 40% of the money that was spent at Tesco came from customers aged under 34, while elsewhere it was 32.2%.
The report describes the Irish market as "going through a period of massive change", with the imminent abolition of the Groceries Order, which banned below-cost selling, likely to have a considerable impact on prices.