The Alberta Securities Commissions regulator has given Canadian Oils Sands a one month extension to find a rival to counter Suncor Energy Inc.'s C$4.3 billion ($3.37 billion) hostile takeover offer.

The regulation raised questions about whether Suncor would keep its bid offer. Canadian Oil Sands may lose Suncor's bid in the process.

The Alberta regulator decision would extend the period for Canadian Oil Sands shareholders to review the bid to Jan 4, one month beyond the Dec 4 expiry date Suncor set for a response to its all-stock bid.

According to CBC News, Canadian Oil Sands put in place a new shareholder rights plan known as a "poison pill" defense after Suncor took all stock bid directly to investors on Oct 5.

The plan would have given Canadian Oil Sands shareholders 120 days to attract a competing offer, or until early February.

Suncor had asked the Alberta regulator to drop down the Canadian Oil Sands' "poison pill", threatening to walk away from the deal if the deadline was extended.

Suncor, Canada's largest oil producer by market value, is seeking to increase its stake in Syncrude bitumen mine from 12 percent currently to roughly 49 percent. Syncrude is largely owned by Canadian Oil Sands.

However, the regulator decided to give Canadian Oil Sand shareholders one-month additional time to accept or reject the takeover.

Bloomberg notes that Canadian Oil Sands board chairman Donald Lowry views the Suncor's offer of 0.25 share for each Canadian Oil Sands share is not the adequate value for the oil-sands miner.

He said that the Canadian Oil Sands will review alternatives, including continuing as an independent company or looking at rival offers to ensure maximum value for shareholders.

Bradley Freelan, a partner at law firm Fasken Martineau said that Suncor has to decide whether or not they are prepared to wait.

Freelan, who has studied hostile takeover bids in Canada said that it would be unusual for Suncor to succeed in acquiring Canadian Oils Sands without some support from the target company's board.

He stressed that only one of 15 hostile takeover cases studied by Fasken Martineau was ended up acquiring the target company without the support of the target company.

According to The Globe and Mail, the highest percentage of competing offers tend to surface 35 to 64 days after the initial bid. There are only two deals in the past decade where competition emerged after 90 days. The additional 30 days is sufficient time to expect a competing bid.

Canadian Oil Sand's single asset, Syncrude, has suffered repeated outages and missed production targets in recent years. Canadian Oil Sands' shares gained 2.8 percent to C$8.56 on Monday in Toronto Stock Exchange while Suncor rose 1.7 percent to C$36.90.