The head of the Swiss National Bank, Philipp Hildebrand, has resigned because of a controversial foreign currency trade made by his wife.
He said he was stepping down with immediate effect to protect the integrity of the central bank.
He quit as Swiss parliamentarians met to discuss the scandal.
Hildebrand told reporters: “Given the ongoing and intense public debate around this financial transaction and after giving considerable thought to the entire situation, I have come to the conclusion that it is not possible for me to provide final and definitive evidence that my wife carried out the foreign exchange transaction on 15 August without my knowledge.”
His wife — a former hedge fund trader who now runs an art gallery — bought dollars when the Swiss franc was strong, three weeks before the bank moved to limit the rise of the franc. She later sold them making a profit of at least 60,000 francs (50,000 euros).
Hildebrand said he had decided the pressure might hurt his ability to take tough decisions to address what he called “probably the most threatening economic and financial situation since the Second World War”.
“I am sad to take this step, I loved this job, I fought like a lion for it,” he said, adding that he had realised that it was probably time to go after Swiss media examined his every move, including where he ate and what his wife was wearing.
In a statement, his wife Kashya apologised to the Swiss people and to her husband for costing him his job.
“I failed my husband by not considering the perception of a ‘conflict of interest’ created by my purchase of dollars,” she said.
“My husband is a man of the utmost integrity, and I deeply regret that my actions might have led anyone to question this.”
The scandal has raised questions about transparency at the central bank, which initially failed to publish its internal ethics codes, saying auditor PricewaterhouseCoopers (PWC) had investigated the trade and found there had been no misuse of privileged information.
The SNB council said on Saturday it would overhaul its internal rules concerning own trading by board members and examine all transactions they made over the past three years.
Hildebrand said the scandal had revealed weaknesses in the SNB’s internal regulations, as well as its requirements in terms of transparency and code of conduct.