Stephen Foley: Olympus shareholders are owed full disclosure on the strange payouts revealed by its ex-boss

Outlook The story of unusual payments surrounding acquisitions by the camera maker Olympus gets curiouser and curiouser. On Tuesday, the Japanese firm's chairman, Tsuyoshi Kikukawa, denied one detail of his sacked chief executive's allegations, disputing the size of the payment to a mysterious "adviser" whose identity can no longer be traced. Yesterday, the company gently corrected its patriarch, and investors were left asking: what on earth is going on?

Whether the payment was 15 per cent of the size of the deal to buy the UK's Gyrus, as Mr Kikukawa claimed, or 36 per cent, as the ousted Michael Woodford alleged and the company now concedes, the size is startling, given typical advisory fees would be about 1 per cent.

Olympus says it did proper due diligence on the Gyrus deal and disputes Mr Woodford's characterisation of his sacking as being connected with his raising of these issues, but there is clearly an urgent need to get to the bottom of these matters. Shareholders have seen the value of their investment halve; they deserve and ought to demand answers, but the investment climate in Japan still tends towards giving deference to management.

Maybe a spot of legal or corporate governance pressure from abroad will help. Mr Woodford has pinned his hopes so far on the Serious Fraud Office in the UK, to which he has passed documents. It would not be surprising if shareholders based in the US, where Olympus has significant operations, seek redress in the courts there, or even push the Department of Justice to examine if there is a case to be brought under the country's tough Foreign Corrupt Practices Act. Olympus shareholders deserve nothing less than full disclosure.