The exclusion of a judge plays an important role in ensuring the judge's impartiality, thus guaranteeing a fair trial and a just decision. The legislator has ensured the implementation of this guarantee in civil proceedings by the institution of the disqualification of the judge by law and at the request of a party or the judge himself. The judge's impartiality may be particularly questionable in cases involving Swiss franc loan agreements due to their prevalence and the banks' concerns about the judge's impartiality. Judges are parties to many contractual relationships and participate in public, social and economic life on the same terms as other citizens. For these reasons, this paper analyzes whether such a judge should be subject to disqualification by law or only upon application.