armanidog: I'm not sure of Japanese law, would anyone who ever bought Olympus stock have a right to file a lawsuit? Hopefully, the board and executives who were found to be aware of the situation will be personally liable for criminal and civil actions. I hope they can not hide behind the corporate structure.
FYI, under American law, directors and officers owe a fiduciary duty to the company, not directly to the shareholders. Shareholders may bring suit against D&Os, but as a "derivative shareholder suit." In other words, you are suing in the shoes of the company; the company as a whole is the plaintiff and wins whatever damages accrue, not individual shareholders.