Skepticism about the deal’s chances is growing.

There is “a significant risk that the deal gets repriced lower,” research firm Hindenburg said about the Twitter purchase in a report earlier this week. Hindenburg has made a name for itself over the past few years because of its bearish reports about electric vehicle startups Nikola and Lordstown Motors.

Hindenburg is shorting Twitter stock, which means the firm would profit if shares fall. Hindenburg noted in its report that “we are supportive of Musk’s efforts to take the company private, and believe he could get it done, but see no reason why he should at these levels.”

Adding more debt to Twitter to help finance the deal would “make it more challenging to pursue Musk’s goal of reducing Twitter’s reliance on advertising, which currently comprises the vast majority of its revenue,” the firm noted.