This article aims to map the political economy of top personal income tax rate setting. A much-discussed driving factor of top rate setting is the corporate tax rate: governments may prefer to limit the differential between both rates in order to prevent tax-friendly saving of labour incomes inside corporations. Recent studies have highlighted several other driving factors, including budgetary pressure, partisan politics, and societal fairness norms. I compare these and other potential determinants in the long run (1981–2018) by studying tax reforms of 226 cabinets in 19 advanced Organisation for Economic Co-operation and Development (OECD) countries using regression models. I find little evidence for the effects of economic, political, and institutional factors; instead, the main determinant of the top rate is the corporate tax rate. As corporate tax rates are still declining under competitive pressure, the recently set minimum rate of 15% will not stop tax competition from constraining progressive income taxation.

The Harmer–Henry pension and tax review resulted in an increase in the common value of the single rate of Age Pension and Disability Support Pension from 25 per cent to 28 per cent of male total average weekly earnings. It also recommended a Resource Super Profits Tax that would have initially taxed mining ‘rents' at 36 per cent, on top of the pre-existing 30 per cent federal tax on profits. These recommendations represent two sides of the same coin: higher federal spending alongside higher federal taxes. The pension rise is likely to reduce participation in the labour force. The proposed tax rise would discourage mining activity as miners considered their options to delay or abandon projects. There is a lot to like at the level of detail in the Harmer–Henry package, but future efforts to reform our tax-transfer system should focus on promoting saving and investment, including investment in human capital.

State-level income tax policy is a hotly debated topic in both academic and political spheres. Although economic theory and some empirical analyses suggest that larger income tax burdens affect migration decisions, there is also a good deal of empirical evidence showing that tax policy has little to no effect. This lack of consensus in the academic literature is echoed in the political world, where many states are debating whether to eliminate income taxes or reduce rates as a means of spurring economic growth. Connecticut’s adoption of an income tax policy in 1991 provides a unique opportunity to analyse the impact of a sizable income tax policy change on migration. The results suggest that Connecticut’s income tax deterred movement into the state but had no impact on exit from the state, resulting in a net loss in migration.