Westpac yesterday confirmed it has appealed the decision of the New Zealand High Court that last month found in favour of the NZ tax authorities on four structured finance transactions undertaken in the early 2000s.Westpac says it believes there are sound arguments that warrant an appeal and that are of sufficient merit to justify consideration by the Court of Appeal.The appeal is unlikely to be heard before the last quarter of 2010, Westpac said.Westpac hasn't confirmed it will make provisions in its full year accounts for the tax amount plus the interest, which works out to around NZ$918 million. It has previously only said the impact on its tier one capital ratios will be of the order of 25 basis points should it increase its provisons.National Australia Bank made a provision of A$452 million for a similar judgement delivered against Bank of New Zealand. BNZ also has appealed against the decision.Both face the task of persuading appeals courts on points of law following some uncomfortable findings by the original judges.The common factor in both the cases, according to judge Rhys Harrison who delivered the Westpac judgement, was the Guarantee Procurement Fee, which was central to the mechanics of the four structured transactions under review in that case."The interposition of the GPF has proved decisive on the facts of both cases," Harrison wrote in judgement.BNZ similarly lost its tax avoidance case, heard by a different judge, because of the way the GPF was interpreted."I conclude that the GPF was a contrivance, substantially overpriced, to increase the tax benefits generated by the transaction," said judge John Wild in his BNZ judgement. "The transactions had no commercial purpose or rationale. Shorn of the tax benefits they were anticipated to generate, they involved the BNZ providing funds to the counterparties at a substantial loss. Their only purpose was to use the Bank's tax capacity to generate exempt income."