Cairn Homes and Lone Star have bought the Ulster Bank Project Clear residential portfolio for £361.6m.
The Irish housebuilding company said it planned to build more than 14,000 new homes across the sites, which have an expected gross development value of more than £1.4bn.
Loans attached to the 1,694-acre portfolio have a face value of around £1.4bn.
Most of the 31 development sites are located in Dublin and the surrounding commuter belt (91%), representing around 20% of the available residentially zoned land in the greater Dublin area.
Cairn has bought a 75% stake in the portfolio, paying £271.7m.
The deal is expected to complete by the end of 2015.
