Waterton bought 912,763 Hudbay common shares on the open market at C$6.4973 for a total investment of $5.93 million.
It previously expressed opposition to Hudbay's commitment to any further mergers and acquisitions, saying the company had enough quality projects to create significant shareholder value.
Waterton had requisitioned a special meeting of shareholders on October 23, to have shareholders vote on adopting a resolution urging the Hudbay board to seek shareholder approval for certain material transactions including acquisitions and joint ventures.
The private investor believes substantial change is required on the company's board to restore its credibility and provide renewed accountability to shareholders, appropriate management oversight, a fresh perspective and highly relevant expertise and skillsets to the board.
Waterton declined repeated requests for comment by Mining Journal on the US$23 million (C$31 million) commitment by Hudbay to buy Mason Resources, which was announced following the meeting's requisition date.
Hudbay has scheduled a special shareholder meeting for February 28, during which owners will consider the advisory resolution regarding potential future transactions.