L’économie racontée par les données bancaires. Ce que nos relevés de comptes disent de nous

Since the health crisis in 2020, the National Institute of Statistics and Economic Studies (INSEE) has had access to anonymized samples of bank accounts from La Banque Postale and Crédit Mutuel Alliance Fédérale. These data, rich in information, have enabled the analysis of the real‑time evolution of households' financial situation during both the unprecedented COVID‑19 crisis and the inflationary episode in 2022. They have also paved the way for the analysis of households' daily situation, highlighting instances of overdrafts at month‑end, and for the evaluation of a public policy by measuring the financial, distributive, and environmental impacts of the fuel subsidy implemented in 2022 following the rise in fuel prices. Bank data are a goldmine of valuable information, but their use raises many challenges. After four years of use, a first assessment of their exploitation is presented in this paper. How can we build economically meaningful concepts from these data? How can we ensure their representativeness? What are the benefits of these data to public statistics? While they do not replace survey and tax data, they complement cyclical analyses. Moreover, they allow us to address long‑standing questions about household consumption and savings that traditional sources could not answer. This paper details the challenges and difficulties in using private data that were not produced for statistical purposes but for the management of bank operations.