251In this case, in the light of all the foregoing considerations, it is sufficient therefore to hold that the Commission failed, in the contested decision, to verify, as it was required to do by the private investor test, whether the rents at issue were lower than market prices. Indeed, the contested decision contains no finding to undermine the position advocated on that point by the applicant during the administrative procedure (see paragraph 241 above). Moreover, the detailed business plan of the experts, set out in the Moore Stephens report on which the contested decision is based, states that the investigations only covered the risk of sub-leasing aircraft to NOA ‘for artificially low rents, even if those rents could have been equivalent to market prices’. However, it is important to note in that regard that, although the Commission may commission outside consultants, without albeit being bound to do so, it is not thereby exempted from assessing their work (Case T-274/01Valmont v Commission [2004] ECR II-3145, paragraph 72).