 Apart from US corporates, and legacy UK corporates (pre 2009–12), there are no foreign corporates in Ireland's top 50 firms.Academics say Ireland is more accurately described as a "US corporate tax haven", and a shield for non–US profits from the historic US "worldwide" tax system.One of the most contested aspects of Ireland's economy is the "aggregate" "effective tax rate" (ETR) of Ireland's corporate tax regime.