Northern Ireland Electricity (NIE) was privatised as a large single company, which owned the systems for electricity for households and businesses across Northern Ireland.
The (then) newly established regulator determined the selling price for electricity to customers at levels which took account of the accepted costs of transmission and distribution. NIE was a regulated monopoly.
The evolution from NIE plc has been dramatic as the original NIE became Viridian Group.
The privatised company was bought by a subsidiary of a company in Bahrain, Arcapita Bank. The Viridian Group has been extensively reorganised. The parent company of the Viridian Group is now Viridian Group Holdings, registered in the Cayman Islands.
The Viridian Group, as registered in Northern Ireland, trades only as a holding company.
Other related businesses are registered in the Republic and the Isle of Man.
An overall aggregation of the totality of the activities of the Viridian Group in Northern Ireland is not published by the group.
The profit and loss account of the Viridian Group in the year to March 2009 was dominated by the receipt of dividends from subsidiaries. It received £110m and paid out £102m to the Cayman Islands parent Group Holdings.
Of the 10 other subsidiaries, four are the largest players in the local electricity business.
NIE Energy employs 97 people and supplies electricity to all households and many businesses. In 2008/9, NIE Energy had a turnover of £1,029m.
Partly because of losses of £42m on hedge contracts, this business made a loss of £17m.
Viridian Energy Supply, which trades as Energia, employs 87 people. On a turnover of £194m there was a pre-tax profit of £3m.
NIE plc, which must be distinguished from NIE Energy, employs 325 people and is mainly responsible for the transmission and distribution business. In 2008/9 turnover was £206m and, excluding discontinued businesses, pre-tax profits were £51m.
NIE Powerteam which engages in infrastructure engineering employed 961 people and is a subsidiary of Viridian Capital. In its own right Powerteam had a turnover of £51m and a pre-tax profit of £0.8m
The 11 companies which report in Northern Ireland had an average employment of 1,493 people last year.
The companies registered in the Republic trade separately from the Northern Ireland companies.