In accordance with Article 23(2) of Regulation No 1/2003, the Commission has the possibility of holding jointly and severally liable for payment of a fine a number of legal persons forming part of one and the same undertaking that is responsible for the infringement. In that context, the Commission’s determination of the amount of the fine — in so far as it is based, in any particular case, on the concept of an undertaking, which is a concept of EU law — is subject to certain limitations, which require due account to be taken of the characteristics of the undertaking concerned, as constituted during the period in which the infringement was committed.

Accordingly, when determining how joint and several liability is to be imposed, from an external perspective, on a number of legal persons forming part of the same undertaking, the Commission is under an obligation, in particular, to adhere to the principle that the penalty must be specific to the offender and the offence, which requires, in accordance with Article 23(3) of Regulation No 1/2003, the amount of the fine imposed to be determined by reference to the gravity of the infringement for which the undertaking concerned is held individually responsible and the duration of the infringement.

However, the rules governing EU competition law, including those relating to the Commission’s power to impose penalties, the EU law principle of personal liability for an infringement and the principle that the penalty must be specific to the offender and the offence, which must be complied with when the power to impose penalties is being exercised, relate only to the undertaking per se, not the natural or legal persons forming part of the undertaking. Moreover, while it follows from Article 23(2) of Regulation No 1/2003 that the Commission is entitled to hold a number of companies jointly and severally liable for payment of a fine, since they formed part of the same undertaking, it is not possible to conclude on the basis of either the wording of that provision or the objective of the joint and several liability mechanism that that power to impose penalties extends, beyond the determination of joint and several liability from an external perspective, to the power to determine the shares to be paid by those held jointly and severally liable from the perspective of their internal relationship. Neither Regulation No 1/2003 nor EU law in general contain rules for determining, in the context of the internal relationship among those held joint and severally liable, the shares of the fine to be borne by each of them individually.

In those circumstances, where there is no contractual agreement as to the shares to be paid by those held jointly and severally liable for payment of the fine, it is for the national courts to determine those shares, in a manner consistent with EU law, by applying the national law applicable to the dispute.

Furthermore, since the power to impose penalties available to the Commission under Article 23(2) of Regulation No 1/2003 does not include the power to determine how the fine imposed is to be allocated as between those held jointly and severally liable from the perspective of their internal relationship, once the fine has been paid in full and the Commission subsequently has no further interest in the matter, so the General Court does not have any such power of allocation when exercising the unlimited jurisdiction conferred on it by Article 31 of that regulation to cancel, reduce or increase such a fine.

(see paras 51, 52, 56, 58, 61, 62, 74)