Viridian Group Ltd — Northern Ireland’s largest energy supplier — hired Macquarie Group Ltd to advise on its bid for the retail and power generation unit of Irish state-owned gas company Bord Gáis, people with knowledge of the matter said.

Centrica, Britain’s largest household energy supplier, picked Citigroup to advise on a potential bid for the retail unit of State-owned gas company Bord Gáis, said three sources.