PayPal has 170 million active users and they're juxtaposed between mobile and PC, Keller said. Lynch said while he doesn't own PayPal, he also sees a lot of disruption in the space. One variable he said is to keep an eye on blockchain technology, with Bitcoin being the best known. While Bitcoin can't be purchased as a stock and its value fluctuates wildly, he is watching the space. "The ability to make payments without a third party could affect … businesses like PayPal," he said.