XBRL for Financial Reporting: Evidence on Italian GAAP versus IFRS

The systematic adoption of the eXtensible Business Reporting Language (XBRL) for financial reporting represents a great challenge. Worldwide, a large number of regulators are making an effort to promote the adoption of this standard to simplify and enhance the communication of financial information. This requires the definition of well‐structured taxonomies that can standardize and accommodate the content of financial reports prepared by firms. This study aims to analyze the regulator‐led adoption of XBRL for financial reporting. It examines the XBRL taxonomies used by Italian firms to reflect their financial reporting under rule‐based Italian GAAP and principles‐based International Financial Reporting Standards (IFRS). We compare the alignment of the Italian GAAP taxonomy and the IFRS taxonomy with Italian companies' financial statements and find two different levels of fit. The results offer useful insights for regulators and policy makers in prescribing or establishing appropriate taxonomies. We illustrate the potential impacts of the different taxonomies on the quality of financial reporting in terms of comparability and potential loss of information.