(12)Once a stock exchange has been authorised, FINMA monitors on an ongoing basis whether it continues to comply with the conditions and duties associated with the authorisation (Article 83 of the FMIA). A stock exchange is legally required to notify FINMA of any changes to the circumstances on which its authorisation or approval was originally based. If the changes are material, the financial market infrastructure must obtain prior authorisation or approval from FINMA to pursue its activities (Article 7 of the FMIA). Key requirements are the compliance with organisational requirements; the existence and effectiveness of the internal control system; the appropriateness of IT systems; and proper business conduct. FINMA's supervision extends to all bodies of the stock exchange including its trading surveillance and sanctioning functions. Pursuant to Article 24, 24a of the FINMASA, FINMA may carry out audits directly, or indirectly through licensed audit companies, both on-site and off-site. Articles 27, 30 and 34 of the FMIA also require all authorised stock exchanges to be able to enforce compliance by their issuers, participants and persons associated with their participants with the provisions of the FMIA and FMIO, associated acts and regulations, and their own rules and regulations. As part of its duty to enforce compliance by their members, the stock exchange is responsible for investigating and disciplining any breaches of the applicable laws and rules.