The chairman of the Swiss National Bank (SNB), Philipp Hildebrand, has resigned with immediate effect, BBC announced yesterday. Hildebrand has faced allegations of wrongdoing after details emerged of controversial currency trades made by his wife. Kashya Hildebrand bought USD 504,000 in August, three weeks before the bank intervened to reduce the value of the Swiss franc. She later sold the dollars to buy a property. The franc rose as high as CHF1.2106 against the euro, its highest since September 20, after Hildebrand decision.