Bill Gurley believes ride-hailing services such as Uber will hurt Hertz's rental car business.

"I think Hertz will face a difficult future," he said at The Sohn Investment Conference in New York on Monday. "Ride-sharing is a huge substitute, and it appears we have a systemic ... massive oversupply of used cars."

Gurley noted the disruption from ride-hailing services is especially dangerous to companies that have large debt holdings, as does Hertz. He also predicts the average cars per household will soon decline.

"We're potentially at peak car. The entire auto industry could change. I think that's a real possibility," he said.

The veteran venture capitalist then shared his thoughts on several technology companies:

Tesla: "You can own the bonds. Elon [Musk] makes it too risky to own the stock."

Amazon: "I'd definitely be long. It's the most respected company."

SoFi: "If you have the highest loan growth volume you probably have the loosest lending standard."

Gurley is a general partner at venture capital firm Benchmark.

Sohn is the most widely anticipated hedge-fund event of the year, where managers volunteer their time and best investment ideas to raise money in the fight against childhood cancer.