Resumen: Investments in circular eco-innovation projects require rigorous measurement and management accounting to assess environmental performance and enable circular economy reporting. Using a double-focused theoretical framework, a methodology is proposed to classify five circular eco-innovation projects in Spanish manufacturing companies. Projects are assessed at implementation under the prism of the resource-based view theory and over time to examine their disclosure in the stakeholder’s theoretical framework. The findings show that companies consistently report sustainability issues and circular economy principles. Specific project information is disseminated punctually, but declines significantly over time, revealing different levels of accountability throughout the lifecycle of circular eco-innovation investments. This study advances circular accounting and the eco-innovation literature by equipping practitioners with tools to compare heterogeneous projects, even during budgeting, and introducing a novel temporal perspective on circular reporting. Given the application of the European Union sustainability disclosure regulations, it also informs the debate on circular accounting and reporting. Policymakers seeking to enhance circular reporting should prioritize monitoring disclosure practices, especially for inter-company and collaborative investments. This paper first introduces the research context, followed by a description of the qualitative research methodology, the main findings, and the conclusions, where the study’s contributions and limitations are discussed. Idioma: Inglés DOI: 10.3390/su17062392 Año: 2025 Publicado en: Sustainability (Switzerland) 17, 6 (2025), 2392 [15 pp.] ISSN: 2071-1050 Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2023-146084OB-I00 Financiación: info:eu-repo/grantAgreement/ES/DGA/S33-23R Tipo y forma: Artículo (Versión definitiva) Área (Departamento): Área Economía Finan. y Contab. (Dpto. Contabilidad y Finanzas)