Under Basel III reforms:

• Systemic risk: Internal models were restricted for calculating capital requirements for systemically important banks
• Operational risk: The Advanced Measurement Approaches (AMA) were eliminated and replaced with the Standardized Approach
• Credit valuation adjustment (CVA) risk: Internal models were restricted for calculating CVA capital requirements
• Credit risk: Internal models (IRB approaches) continue to be permitted for credit risk measurement, though with some constraints and floors

Therefore, credit risk is the only category where internal model approaches were NOT restricted under Basel III reforms.