Shares in AIB fell back below the €1 level, after dropping more than 9% in value at one stage in trading today. The shares finally closed 4.6% lower at €1.04.
Bank of Ireland enjoyed a mixed day and closed 3% higher at €1.22 after falling by 5% earlier. Bank of Ireland's shares closed at €1.18 on Friday.
One analyst said the shares had slumped following comments by the Central Bank Governor Patrick Honohan on RTE's Week in Politics programme. He said there was a likelihood of increased state ownership and consequent dilution of share value that would entail.
He described the two main listed Irish banks as 'friendless'.
The Governor of the Central Bank also said he believed there will be an inquiry into the causes of the crisis in the Irish banking system.
Professor Patrick Honohan said he could not fully understand why the country's oldest banks fell into a trap where they could lose a lot of money.
The Governor told an Oireachtas committee last week that he would have liked to have seen a greater proportion of risk-sharing between the banks and the State in the establishment of the National Asset Management Agency.
Professor Honohan said such an inquiry should examine the wider social issues that gave rise to a rapid escalation in risky lending to commercial and personal borrowers.
