Olympus Corp said on Friday a Japanese investor expanded the scope of a shareholder lawsuit against former and current executives at the scandal-ridden company, whose shares have slumped 60 percent in six weeks.

The unnamed individual, who lives in western Japan and owns an undisclosed number of shares, has widened the suit to include 37 executives, up from 21, and wants the company's auditors to pay damages as well, Olympus said in a statement.

The shareholder is asking for 149.4 billion yen ($1.9 billion), 10 billion yen more than originally sought, from executives found to have failed to meet their fiduciary responsibilities.

Under this type of shareholder representative suit, the repayment of alleged losses is to the company rather than to individual shareholders.

The shareholder is asking that Olympus's 11 auditors and two auditing companies who signed off on acquisitions that were used to hide investment losses also pay damages of 149.4 billion yen.

A U.S. investor, Lloyd Graham, has also filed a securities lawsuit against the Japanese camera and endoscope maker, seeking class-action status and accusing Olympus of making false statements about its finances and intentionally hiding losses from investors.

Olympus shares closed in Tokyo on Friday at 1,107 yen, up nearly 9 percent, after touching a 4-week high of 1,276 yen.

(Reporting by Mayumi Negishi; Editing by Joseph Radford and Ian Geoghegan)

Japan Lawsuit