Wikipedia
MaRisk is a referring to the minimum requirements for risk management (German Mindestanforderungen an das Risikomanagement), a circulaire by the German Federal Financial Supervisory Authority (Bundesanstalt für Finanzdienstleistungsaufsicht, BaFin) providing concepts for risk management of banks, insurances and other companies financially trading in Germany. The primary legal background for MaRisk is the Kreditwesengesetz (KWG), the secondary legal background is the Solvabilitätsverordnung SolvV.
The MaRisk implements the qualitative requirements of Basel II and Basel III into German law. Strictly speaking, MaRisk is not a law, but a norm-interpreting administrative regulation (German normeninterpretierende Verwaltungsvorschrift), nevertheless it is de-facto binding for all financial institutes and insurances with business in Germany.