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.

April 21, 2026 – 14.30h – Room 1038

5 de desembre de 2025 – Districte Administratiu, Generalitat de Catalunya – 11h-13h

December 16, 2025 – 14.30h – Room 1038

Enforcing wealth tax compliance among high-net-worth individuals is particularly challenging. Using administrative data on the Net Wealth Tax for Catalan taxpayers over the 2011–2020 period, this paper evaluates the impact of audits on voluntary compliance. The evidence suggests that wealth tax audits do enhance compliance, but the impact is short-lived — and driven by taxpayers rebalancing their tax evasion and avoidance responses. On the institutional side, the results indicate that Spain’s overlapping tax audit mandates can create coordination frictions that reduce the efficiency and effectiveness of audit-based enforcement of the New Wealth Tax. Effective enforcement depends not only on robust audit strategies, but also on coherent institutional design and sound tax policy.

Las estructuras federales de gobierno, bien diseñadas, consiguen compatibilizar la provisión centralizada de bienes
públicos puros (Federalist Papers, No. 30) con mejoras en la eficiencia asignativa a través de la provisión descentralizada del resto de bienes públicos (Oates, 1972). En España, el mejor ejemplo reciente de la provisión de bienes públicos puros – incluyendo la colaboración con un nivel supranacional de gobierno, como es la UE – ha sido la gestión de la COVID-19 (provisión de vacunas o concesión de ayudas financieras a los sectores económicos más afectados), mientras que, en el segundo caso, Espasa et al. (2017) demostraron que la satisfacción de la población mejoró a raíz de la descentralización de las políticas relacionadas con el Estado del Bienestar.