Healthcare executives are keeping their eyes on Amazon. And given the tech giant’s expanding reach in healthcare, that’s not too surprising.

But when KLAS Research asked more than 300 healthcare leaders to identify the most potentially disruptive company in healthcare, they found plenty of smaller, emerging companies getting a lot of buzz as well.

The company names that were dropped could indicate the healthcare problems executives are most focused on solving right now.

Among the top companies frequently mentioned: Cedar, a patient payment and engagement platform, according to KLAS Research’s survey. Cedar, launched in 2016, offers patient-personalized medical billing, and the company has raised $49 million in venture capital funding.