Abstract
The paper examines the impact of the institutional context and the regulation on the disclosure
of non-GAAP indicators (NGIs), with a focus on the adoption of NGIs for opportunistic purposes. We
firstly discuss the concept of opportunism and the approaches to discover opportunistic behaviours in
the adjustment process. Then, we define a new procedure in three steps to highlight opportunistic
behaviours. Based on a sample of 120 international listed companies, from 23 countries included in the
S&P Global Oil Index, we employ logistic panel regression models to test our hypotheses about the role
of the institutional context in affecting opportunism. First results suggest that while strong institutional
contexts (developed market, high-quality legal system, protection for minority shareholders, common
law system) reduce the disclosure of NGIs, they increase opportunistic behaviours. Moreover, the
introduction of a regulation on NGIs increases the general disclosure of adjusted measures, but it does
not moderate the opportunistic use of NGIs. Our research contributes to the non-GAAP literature
providing a practical approach for measuring opportunism in NGIs disclosure. At the same time, the
results provide useful insights to regulators and standard setters about the role and the effectiveness of
regulations on NGIs in different institutional contexts.