As the European Central Bank is elaborating a purchase program in order to face the current crisis, the institution also bears in mind that the German constitutional court might sue if they think that the ECB exceeds its level of competence. Finance professor at HEC Paris Business School comments for Bloomberg: "Legal uncertainty will hang over the ECB like the sword of Damocles. That risks reining in the ECB because policy makers can’t be absolutely sure they’re in the clear. It also threatens to undermine the tool’s full effectiveness if markets get the impression there are legal problems ahead."