This report, commissioned by the Brazilian G20 Presidency ahead of the July 2024 G20 Finance Ministers and Central Bank Governors meeting, contributes to discussions on the role of tax systems in addressing inequality. It explores how tax systems can mitigate or exacerbate inequality with a focus on the distribution of income and wealth and identifies scope for potential reform. It zooms in on the specific tax policy and compliance challenges associated with taxing high-net-worth individuals (HNWIs), some of which have a cross-border dimension.