The unsolicited bid put on the table by Suncor Energy is far below what represents a fair value, a main shareholder at target Canadian Oil Sands said.

Suncor Energy, the largest energy company in Canada, offered about $3.2 billion for rival Canadian Oil Sands Ltd. in a hostile bid. Seymour Schulich, a Canadian billionaire with a 5 percent stake in Canadian Oil Sands, told the nation's Financial Post newspaper the offer was off target.

"It's not a low-ball offer, it's a no-ball offer," he said. "The bid is ridiculous."

In a formal statement, Canadian Oil Sands said it was reviewing the offer with its financial advisers.

"Shareholders are urged not to take any action or make any decision with regard to the Suncor offer until the board [of directors] has had an opportunity to fully review the Suncor offer and to make a recommendation as to its merits," the company said.

Suncor said the bid would alleviate some of the debt obligations for its rival and result in a dividend increase of 45 percent for shareholders. Suncor President and Chief Executive Officer Steve Williams said the offer put on the table was "financially compelling."

Suncor started 2015 by making "significant spending reductions" in its budget, which included an $830 million cut in capital spending and operating expense reduction of around $580 million over two years.

The cost-cutting effort included a hiring freeze and the elimination of 1,000 positions from its payroll.