In its ING Groep Judgment, the CJEU determined that the Commission could not evade its obligation to assess the economic rationality of an amendment to the repayment terms of the aid granted by the Dutch State to ING in the light of the private investor test solely on the ground that the capital injection subject to repayment itself already constituted State aid--since only after such an assessment would the Commission be in a position to conclude whether an additional advantage within the meaning of Article 107(1) TFEU had been granted.
30 [...] in view of the objectives pursued by Article [107(1) TFEU] and the private investor test, an economic advantage must, even where it has been granted through fiscal means, be assessed in the light of the private investor test if, on conclusion of an overall assessment, it appears that, notwithstanding the fact that the means used were instruments of State power, the Member State concerned has conferred that advantage in its capacity as shareholder of the undertaking belonging to it.
31 It follows that the applicability of the private investor test to a public intervention depends, not on the way in which the advantage was conferred, but on the classification of the intervention as a decision adopted by a shareholder of the undertaking in question.
32 Furthermore, that test is one of the factors which the Commission is required to take into account for the purposes of establishing the existence of aid and is therefore not an exception that applies only if a Member State so requests, where the constituent elements of State aid incompatible with the common market referred to in Article [107(1) TFEU] have been found to be present (see Commission v EDF, paragraph 103).
33 Consequently, where it appears that the private investor test may be applicable, the Commission is under a duty to ask the Member State concerned to provide it with all relevant information enabling it to determine whether the conditions governing the applicability and the application of that test are met (see Commission v EDF, paragraph 104).
34 The application of that case-law cannot be compromised merely because, in this case, what is at issue is the applicability of the private investor test to an amendment to the conditions for the redemption of securities acquired in return for State aid.
35 Indeed, as the Advocate General has stated [...] any holder of securities, in whatever amount and of whatever nature, may wish or agree to renegotiate the conditions of their redemption. It is, consequently, meaningful to compare the behaviour of the State in that regard with that of a hypothetical private investor in a comparable position (C-224/12 at paras 30-35, emphasis added).