The department "Supervision of Investment Firms" is in charge of the supervision of investment firms, i.e. investment advisers, brokers in financial instruments, commission agents, private portfolio managers, professionals acting for their own account, market makers, underwriters of financial instruments, distributors of units/shares in UCIs, financial intermediation firms and investment firms operating an MTF in Luxembourg.

The supervision of investment firms is carried out based on periodical financial information that they must transmit, on the on-site inspections and on the analysis of the comments and assessments provided by the réviseurs d'entreprises agréés (approved statutory auditors) and internal auditors of investment firms.

Where investment firms have subsidiaries or financial holdings in Luxembourg or abroad, the undertakings concerned are subject to prudential supervision by the CSSF on a consolidated basis, in addition to the prudential supervision on an individual basis.