Hildebrand's decision to relinquish one of the world's top central banking jobs after just two years came as Swiss parliamentarians met to discuss the scandal, which erupted last week after Sarasin bank sacked an employee who leaked details of the trade to a political opponent of the central banker.

Hildebrand's wife Kashya, a former hedge fund trader who now runs a Zurich art gallery, bought 400,000 Swiss francs ($418,000) worth of dollars on August 15, three weeks before her husband oversaw steps to cap the rise of the safe-haven franc. She later sold the dollars at a higher rate.