Wealth inequality and preferences in the design of a Wealth Tax: An information-provision experiment in the UK and Spain

We study perceptions of wealth inequality and preferences over the design of a wealth tax through representative online survey experiments in the United Kingdom and Spain, fielded in 2023. After eliciting prior beliefs about the top-10% and bottom-50% wealth shares, we randomly show respondents the true statistics and measure effects on support and the preferred design: exemption threshold, rate and asset base. In both countries baseline support is high (over 80%), the modal preferred threshold is £/€1M, a low (0.5%) rate is preferred to a higher (1.5%) one, and most respondents exempt primary residences and pension wealth. The average treatment effect on support, threshold and rate is close to zero, reflecting a high-support ceiling and a weak link between perceived inequality and tax preferences. Even the comprehenders who demonstrably revise their beliefs, raising perceived inequality by 0.4-0.5 points, are no more supportive, a clean belief-to-preference dissociation. Information campaigns are therefore unlikely to broaden an already large base of support, though they can reshape design where the ceiling does not bind. This occurs only in Spain, and only for a particular attitudinal configuration: corrective information lowers the preferred threshold among supporters who see inequality as unfair (family origin, not effort, driving success) and trust that taxation is useful and well spent, with the largest effect, about three times the all-supporter average, where the two coincide. No UK subgroup responds, its priors being more accurate and the two attitudes coinciding far less.