Investment services providers, other than portfolio management companies, authorised in France, intermediaries authorised by the Autorité de contrôle prudentiel et de résolution for clearing, administration or custody of financial instruments, and market undertakings authorised to provide the investment services referred to in Articles 8 and 9 of Article L. 321-1, shall adhere to a securities guarantee mechanism. The purpose of this mechanism is to compensate investors in the event that their financial instruments and cash deposits become unavailable when they are linked to an investment service, the clearing or custody of financial instruments and do not fall within the scope of 1° of II of article L. 312-4. Persons and funds excluded from compensation under article L. 312-4-1 are not eligible for the guarantee mechanism.