6. The producer, in the case of individual fulfilment of extended producer responsibility obligations, or the producer responsibility organisation entrusted with carrying out those obligations, in the case of collective fulfilment of extended producer responsibility obligations, shall provide an adequate guarantee intended to cover the costs related to waste management operations owed by the producer or the producer responsibility organisation, in the event of non-compliance with the extended producer responsibility obligations, including in the permanent cessation of its operations, or insolvency. Member States may specify additional requirements for the guarantee. The guarantee may take the form of a public fund that is financed by producers’ fees and for which a Member State is jointly and severally liable.