BUSINESSMAN Mr Denis O'Brien is understood to be close selling the Stack B building in Dublin docks for £5 million.

The 14,000 square foot building is located in the International Financial Services Centre and has substantial tax allowances associated with it.

Mr O'Brien is the major shareholder in Communicorp, the parent of Esat Telecom and owner of the Dublin radio station, 98FM. Esat Telecom is a 37.5 per cent shareholder in Esat Digifone, the consortium which plans to construct and operate the second mobile phone service this year.

Esat Digifone recently leased three floors of the former Bord Na Mona headquarters building on Baggot Street, Dublin. The company took 24,000 square feet space on the ground, first and second floors.

It is believed that Mr O'Brien decided to dispose of the stack B building as it was not required for any of his business interests. Esat Telecom moved into new offices on Grand Canal Quay last year.

The Stack B building was on the market for about six weeks, after efforts to lease it proved unsuccessful.

Communicorp is in the process of combining its interests in Esat Digifone and Esat Telecom into a separate company, Esat Holdings, as part of a fund raising operation. The group is seeking to raise £30 million in debt to fund Esat Telecom's expansion and meet its share of the projected £100 million cost of building the Esat Digifone network.

The other shareholders in Esat Digifone are the Norwegian state phone company, Telenor, which has 37.5 per cent and Mr Dermot Desmond's investment company, International Investment and Underwriting which has 25 per cent.