The head of the Swiss National Bank has stepped down after a scandal involving a controversial currency trade made by his wife. In a statement, the bank said Philipp Hildebrand's resignation takes effect immediately.

Hildebrand on Thursday denied any wrongdoing, following media reports about alleged insider trading on a dollar trade his wife made in August. She made the trade three weeks before her husband directed the bank to put a cap on the rising Swiss franc.

The currency deal netted a huge profit.