Corporate reporting increasingly relies on financial key performance indicators (KPIs) to supplement the financial figures required by Generally Accepted Accounting Principles (GAAP). However, the lack of standardized definitions for KPIs raises concerns about their comparability and consistency. We experimentally examine how two features of financial KPIs—KPI type (standardized vs. management-defined) and KPI performance (positive vs. negative)—jointly influence investor judgment under different disclosure regimes (required vs. permitted). We find that under a required disclosure regime, standardized KPIs lead to a higher willingness to invest than management-defined KPIs when KPI performance is positive, whereas the pattern reverses when performance is negative. In contrast, under a permitted disclosure regime, positive KPIs increase investment willingness regardless of KPI type. Our study extends the non-GAAP literature by providing evidence on the role of financial KPI standardization and by disentangling discretion in metric construction from discretion in disclosure decisions for shaping investors’ judgments. Our findings offer timely insights for regulators and practitioners.