The surprise takeover bid for Toshiba Corp. is a palpable demonstration of the growing influence in corporate Japan of activist investors, who have gone from largely impotent onlookers to kingmakers in the space of just a few years.

The offer from CVC Capital Partners, while still in the early stages, comes just weeks after Toshiba Chief Executive Officer Nobuaki Kurumatani lost a landmark shareholder vote, forcing an independent investigation into alleged issues with voting at its annual general meeting last year.

That loss has piled pressure on Kurumatani, who barely won re-election at last year’s meeting and is seen as unlikely to survive another. The vote was triggered by Toshiba’s largest shareholder, the secretive Singapore-based hedge fund Effissimo Capital Management.