Some 77% of global private companies and 70% of those with US parent companies say tax issues are a significant factor in deciding where to establish an operating base overseas. According to Grant Thornton's annual International Business Report, the importance that overseas companies looking to do business elsewhere place on tax 'does not bode well for the UK', particularly in light of the current environment where there is continuing uncertainty surrounding the tax system. Some 57% of UK private companies said tax was a significant factor when investing overseas, possibly reflecting the relative simplicity of other tax regimes for UK business compared to domestic rules and regulations. Roopa Aitken, international corporate tax partner at Grant Thornton, said: 'It is interesting to compare the UK statistic for private companies in light of the recent rise in larger listed multinational corporations such as Henderson, Charter and Regus, who have relocated their parent company out of the UK, with the bulk of the recent relocations going to Ireland.'