Canadian Oil Sands announced its entire board of directors is comprised of former leaders from rival Suncor as a hostile takeover takes hold.

Suncor last week acquired 72.9 percent of the shares in Canadian Oil Sands last week after a release from independent stakeholders. The company made an all-stock offer for its rival last year.

In a statement, Canadian Oil Sands said Harry Roberts, a former vice president at Suncor, is now serving as the chairman of the board, replacing Don Lowry. All five members of the board are former Suncor executives. Sandy Martin, the new CEO, served previously as Suncor's vice president of commercial development. He replaces Ryan Kubik.

Lowry and Kubik worked to persuade Canadian Oil Sands shareholders it was better positioned as a standalone company.

Suncor in late 2015 made an estimated $3 billion hostile bid to acquire all stocks in Canadian Oil Sands. Both companies are stakeholders in the Syncrude oil sands processing facility in Alberta, though Canadian Oil Sands held the most shares in the operation.

Lowry in mid-January said shareholders sent a "loud and clear" message to Suncor when they rejected a second offer from its rival.

Canadian Oil Sands management criticized the bid as opportunistic, though Suncor said it could help return value to shareholders. Last week, Suncor reported an operating loss of $18.9 million and a net loss of $1.45 billion for the fourth quarter.

Suncor has called in rival shareholders to give up their outstanding options before Feb. 22.