Shareholders of Japanese drugstore chain operator Tsuruha Holdings will vote Monday on a proposal which effectively results in its acquisition by supermarket chain Aeon, a move that has already been panned by major investors and proxy advisers.

The chorus reflects rising shareholder activism in Japan in recent years as the country’s governance reforms embolden investors. Their disappointment in the planned deal centers around the perceived low premium it would pay to Tsuruha shareholders.

Aeon, the country’s largest supermarket chain operator, last month said it will launch a tender offer to make Tsuruha a consolidated subsidiary at ¥11,400 per share as it tightens its grip on the drugstore market.