Tax planning as a family matter: Intra-household organization and inequality

Abstract

We study how tax planning is organized within households using administrative data from the SpanishWealth Tax. Exploiting individual-level information on asset holdings and tax liabilities, we document strong intra-household comovement across legally defined planning margins, indicating that tax planning is a family matter. The strength and form of this comovement vary systematically with the internal distribution of wealth within the household. Behavioral responses are initially symmetric across spouses, consistent with bilateral coordination. As intrahousehold wealth inequality increases, however, symmetric coordination weakens and gives way to increasingly asymmetric responses, particularly for flexible asset-based margins. This patern is consistent with a shift toward a more hierarchical organization of tax planning centered on a single household member who controls flexible, tax-advantaged assets. Additional descriptive evidence shows that the relationship between intra-household income inequality and wealth inequality departs systematically from a simple proportional benchmark, in ways consistent with non-trivial within-household organization of resources rather than mechanical ownership structures. Together, these findings highlight the importance of intra-household inequality for understanding the organization, enforcement, and incidence of wealth-tax planning.