The new group is to be called The Mercantile Group
Two bar groups are to merge to create one of the largest hospitality groups in the country.
The Mercantile Group and the Capital Bars Group - which will be known as the Mercantile Group - will employ approximately 600 people and have revenues of approximately €40m per annum.
The merger is expected to be completed shortly.
Before the merger, the Mercantile Group was controlled by Frank Gleeson, while the Capital Bars Group was controlled by Danu Investment Partners, a Dublin-based private investment firm led by Mark O'Meara, Leonard Ryan and Michael O’Rourke.
The enlarged group will control 12 venues:
The new Mercantile Group will be led by Frank Gleeson, who will oversee development and expansion.
The group says a "significant capital expenditure programme" is planned.
Mr Gleeson commented: "This is a transformational deal for our businesses and will position the Mercantile Group at the forefront of the sector in Dublin".
"We have ambitious plans to grow the business further both in Dublin and internationally and we are looking forward to a very exciting period ahead", he added.
A spokesman says there will be no job losses, and they are likely to hire more staff for the South William Street venue in the near future.