Canadian Oil Sands Ltd. said it was urging shareholders to reject a hostile bid from its counterpart Suncor, arguing it's positioned well for falling oil prices.

"Suncor wants you to believe that Canadian Oil Sands is at risk in a low oil price environment, but the fact is it is much more resilient in a 'lower-for-longer' oil price environment than Suncor wants you to realize," a letter to shareholders read.

Suncor is making a hostile bid for Canadian Oil Sands, its co-venture partner at Canada's mega Syncrude oil sands production facility. Suncor President and Chief Executive Officer Steve Williams said the offer is "fair."

Suncor is a minority stakeholder in the Syncrude oil venture in Alberta. Canadian Oil Sands holds a 37 percent stake in the project. Several major oil and oil services company are in the process of merging in an effort to streamline operations, but Canadian Oil Sands said Suncor is the one at a disadvantage in current market conditions.

"Syncrude will produce more oil if they own your interest in the project, but it has been an owner for the past six years and not offered any silver bullets," the letter read.

Suncor argued in a mid-December letter to rival shareholders it could take up to a decade before shares in Canadian Oil Sands are posting a "significant" dividend. "Hope," the Suncor letter said, is not a viable business strategy.

In response, Canadian Oil Sands said it was the one returning more value to shareholders, with about $12 per share in returns since 2001. That would've been about 10 percent less had Suncor controlled the shares, it argued.

Suncor's bid for Canadian Oil Sands expires Jan. 8.