"You never want to say 'never.' There are a lot of large U.S.-based tech companies that have big piles of offshore cash that they could use to finance an acquisition like this," Gillis said Monday on CNBC's "Squawk on the Street."
Gillis also said BlackBerry is still modestly priced at $9 a share.
"This is still a 'take-under' bid. You look at the average one month price for BlackBerry, it's $10.32, so this $9 bid is a take-under," he said.
But the chance of another buyer stepping up is hard to believe, even with shares priced at where they are, said Carolina Milanesi, an analyst for Gartner.
Milanesi said that she thinks a deal with Fairfax will occur because there is no other interested party who would want all of BlackBerry's business, especially its handset business.
It doesn't make sense for someone who is only interested in certain BlackBerry assets to buy the entire company; it makes more sense for potential buyers to wait until BlackBerry figures out what assets it plans to sell as a private company because they will get a better deal, she said.
"Other interested buyers are waiting to see what happens afterwards," she said. "They want to wait and see what happens to the pieces after the company goes private, to see what they will keep and what they will sell. They are better off for waiting," she said.
—By CNBC's Cadie Thompson. Follow her on Twitter @CadieThompson.