There are calls for a wider inquiry into trading practices at Davy Stockbrokers -- and personal sanctions for those involved in a 2014 bond deal.
Four days of mounting pressure following a Central Bank inquiry led to the resignation of its chief executive and two senior figures in the firm yesterday.
Opposition parties have written to the governor of the Central Bank saying the fine of 4.1 million euro is not enough.
Sinn Féin's Pearse Doherty says there must be a full inquiry into all 16 individuals involved in the deal.
He says they deal with too much State money for light-touch regulation.