Toshiba Corp. shareholders voted on Thursday in favor of an independent investigation into allegations that investors were pressured ahead of last year's annual general meeting — a landmark win for corporate governance in Japan.

The vote marks only the fourth time that a shareholder motion has won approval in Japan and the first at a major company that is a household name, albeit one sullied by a string of scandals.

"This result shines a very public spotlight on the likelihood that EGMs, which in Japan can be called by a shareholder that has owned only 3% for 6 months, will probably be used more by activists," said Nicholas Benes, a corporate governance expert and representative director of the Board Director Training Institute of Japan.