Shareholders led by U.S. buyout fund Steel Partners ousted the management of wigmaker Aderans Holdings Co. on Thursday in a revolt signaling investors are winning more influence over how Japan's companies are run.

Chief Executive Officer Takayoshi Okamoto and six directors of the nation's biggest wigmaker were voted out during a shareholders' meeting when the company sought approval of reappointing them to their positions, company spokeswoman Maki Ichikawa said.

It is rare for a shareholder to succeed in forcing out the top management of a publicly traded Japanese company. And it is likely the first time this has happened at the hands of a foreigner, said Hiroyuki Araki, director of mergers and acquisitions at Mirai Consulting Inc. in Tokyo.