Olympus head Tsuyoshi Kikukawa resigned yesterday after a scandal over hefty advisory fees wiped out half of the 92-year-old firm’s market value while his successor stuck with the company’s line that it had done nothing wrong. Sources said Japan’s securities watchdog was looking into past Olympus takeover deals.

Olympus fired its British chief executive, Michael Woodford, on October 14th, just two weeks after his appointment as CEO, Mr Kikukawa then took over Mr Woodford’s role.

Mr Woodford said he was sacked for questioning a $687 million advisory fee linked to a $2.2 billion takeover in 2008 as well as other deals he says have destroyed about $1.3 billion of shareholder value. He has called for the resignation of Olympus’s entire board.