Principles established in Accenture’s recent royalties tax row with the Revenue Commissioners have held firm in the latest appeal to make its way to the High Court. Justice Marguerite Bolger has reaffirmed that withholding taxes levied on overseas sales are not a deductible business expense under the Irish tax code. This time the applicant in the spotlight was Avaya, an American multinational technology company headquartered in New Jersey. It provides call-centre and workplace collaboration technology, typically to large businesses, healthcare providers, and government agencies. The company originated as a spin-out from Lucent Technologies, itself formerly part of communications giant AT&T.…