Shareholders in PTSB bank will vote today on whether to accept a €1.6 billion takeover offer from Austrian group Bawag at an extraordinary general meeting in Dublin.
The State, which owns 57.4% of the shares, has backed the deal.
However, the offer needs acceptances from 75% of shareholders before it can proceed.
A number of shareholders have expressed reservations at the price offered for the bank.
The deal was recommended by the PTSB board in April.
Sretaw, an investment vehicle owned by businessman Eamon Waters which owns 7.02% of the bank, initially said it was disappointed by the deal.
A leading advisory firm Glass Lewis has recommended that shareholders reject the offer and said it looks increasingly "tenuous" as bank share prices have steadily risen.
However, another proxy advisory firm ISS has backed the deal.
The offer for PTSB is €400m less than the value of PTSB's net assets at the end of last year.
However, the offer of €2.97 per share is above the company’s share price before a sales process was announced in October.
The Irish bank argued the Bawag offer represented the best deal for shareholders.
PTSB put itself up for sale last year and appointed advisors Goldman Sachs to conduct a competitive process.
Yesterday the Irish bank’s CEO Eamonn Crowley said: "The PTSB Board’s decision followed a thorough evaluation of value, certainty, stakeholder considerations, and long-term strategic fit."
Minister for Finance Simon Harris has also supported the deal.
Other large shareholders are Samson Rock Capital with 3% of the stock, Morgan Stanley 3.1%, Goldman Sachs 3.15%, UBS 3.6% and Wellington Group 5.9%.
If shareholders agree to the deal it would also have to be approved by the High Court in Ireland and the European Central Bank in Frankfurt.
