"The hemophilia business is so good — and remember, the insurance companies pay for it — that many other companies are trying to get a piece of it," the "Mad Money" host said.
More innovative competitors like Shire, CSL Behring, Roche, Bayer, and Novo Nordisk are coming to the fore and putting Bioverativ's massive potential future sales at risk.
"If any of Bioverativ's competitors seem like they're onto something, this stock could get pounded," Cramer said. "We're entering an extended period where we could potentially get lots of good news about the competition, and no real, significant news about Bioverativ's own pipeline. That's not good."
So while the company has a lot of potential, Cramer worries about what may come out of its competitors to threaten the stock. And if you've researched the stock and fallen in love, you have his blessing to speculate, not invest.