The Dublin bourse has asked listed companies, corporate finance advisers, investors and analysts for their views on a potential change to so-called free floats, said Brian Healy, director of trading and regulation at the Dublin bourse.

The measure would bring Dublin into line with the world's biggest stock markets in the US and Britain.

Financial stocks make up the biggest group in Ireland's 56-member Iseq overall index, which is tracked by many Irish pension funds, said John Cantwell, an analyst at NCB Stockbrokers in Dublin.

"The free-float methodology has become the norm at this stage, certainly in respect of national benchmarks, " Healy said. "It affects every fund out there tracking the index and should make it easier for them to track it."

Under free-float rules, the weighting of Dublin based AIB, the Iseq's biggest stock, would rise to 18.1% from 17.1%, while Bank of Ireland's would rise to 14.7% from 14%, Cantwell estimated in a note to investors.

The overall weighting of Irish financials would rise to more than 47% from 45%, he said.