On 28 April 2015, the Swiss Federal Administrative Court set aside a summons to appear as a witness issued by the Swiss Financial Market Supervisory Authority (FINMA) against a former employee of a Swiss financial institution.

Based on a request of the UK Financial Conduct Authority (FCA) for international administrative assistance in connection with the manipulation of the GBP Libor, FINMA invited the appellant to be heard on a voluntary basis as a person providing information (Auskunftsperson). After the appellant refused to accept FINMA's invitation and asked to be summoned by an appealable order, FINMA subpoenaed him as a witness.

The court ruled that third parties should be interrogated as persons providing information and have, in contrast to witnesses, an absolute right to remain silent. Moreover, they can-not be punished for giving false testimony. Only if the third parties refuse to disclose crucial information or the accuracy of their statements is questionable, they may be summoned as a witness. The court held that the appellant was entitled to request and challenge the summons, and that the exercise of these rights gave no pretext to FINMA to subpoena him as a witness. The appellant was represented by Roberto Dallafior and Patrik Salzman (Decision B-3201/2014).