Article 25 of Regulation No 1/2003 sets the limitation period for the imposition of penalties at five years, reduced to three years in the case of infringement of provisions concerning requests for information or the conduct of inspections. No penalty may be imposed on an undertaking for which it cannot be established that it participated in facts that occurred less than five years before the investigation started. Time begins to run on the day on which the infringement is committed or, in the case of continuing or repeated infringements, on the day on which the infringement ceases. Any action taken by the Commission or by the competition authority of a Member State for the purpose of the investigation or proceedings in respect of an infringement interrupts the limitation period insofar as the action has been notified to at least one undertaking or association of undertakings having participated in the infringement.  Such is the case where there has been: a request for information, inspections, the initiation of proceedings, a Statement of Objections or a decision to grant partial immunity to a leniency applicant. The interruption also applies for all the undertakings that participated in the infringement, including those which are not identified as such in the Statement of Objections. The inspection decision of the Commission carries the same effect of suspending the limitation period in respect of all the undertakings having participated in the infringement, even if some of them have not been notified thereof. Each interruption starts time running afresh. However, the inter partes – and not erga omnes – effect of the suspension attached to judicial proceedings by Article 25(6) of Regulation No 1/2003, prevents the addressees of a final decision not having brought an action for annulment from benefiting from the suspensive effect derived from the action brought by another addressee of the same decision. The limitation period shall expire at the latest on the day on which a period equal to twice the limitation period has elapsed without the Commission having imposed a fine or a periodic penalty payment. Lastly, the limitation period is suspended as long as proceedings are pending before the Court of Justice.

The enforcement of Commission decisions imposing a sanction (fine or periodic penalty payment) is also subject to a limitation period of five years which begins to run on the day on which the decision becomes final (Regulation No 1/2003, Article 26). It may be interrupted either by notification of a decision varying the original amount or refusing an application for variation, or by an action designed to enforce payment. It is suspended for so long as time to pay is allowed or enforcement of payment is suspended pursuant to a decision of the Court of Justice.

Lastly, pursuant to Article 7(1) of Regulation No 1/2003, ” [i]f the Commission has a legitimate interest in doing so, it may also find that an infringement has been committed in the past”. That provision enables the Commission to establish the existence of a time-barred infringement without imposing a fine, where such a measure allows it to reinforce its finding that a single infringement, which is not time-barred, has been committed.