Tesla CEO Elon Musk is telling his employees they need to cut costs or they can kiss its lofty stock price goodbye.

Tesla shares have been among the best performers in 2020, rising nearly 600% through Tuesday trading, making it among the most valuable stocks in the country, worth more than any major automaker. After years of losses Tesla has now reported five straight quarters of positive net income.

But in an email to employees Musk acknowledged that Tesla’s actual profit margin is fairly low, only about 1%, and that the stock price is due to investor expectations of future profits rather than recent results.

“If, at any point, they conclude that’s not going to happen, our stock will immediately get crushed like a soufflé under a sledgehammer!” he wrote in the email, which was first reported by Electrek. Tesla did not respond to a request for comment about the email.

The email was primarily focused on the importance of finding even small cost savings in the car building process.

Tesla faces continuing federal safety investigation – but it’s headed for S&P 500

“This a tough Game of Pennies — requiring thousands of good ideas to improve part cost, a factory process or simply the design, while increasing quality and capabilities,” Musk wrote. “A great idea would be one that saves $5, but the vast majority are 50 cents here or 20 cents there.”

While Tesla has become the leader in electric cars, all the top automakers are making major pushes to build more electric vehicles. General Motors has announced plans to switch to nothing but electric vehicles, and expects 40% of the cars it sells to be electric within five years. Part of the incentive is that electric vehicles can be cheaper to build because they have fewer moving parts than gasoline powered vehicles.

In separate comments Tuesday, Musk repeated a statement he has made previously that the Tesla stock price is “too high.”

“I even said the stock was too high. I mean what am I supposed to do,” he said while rolling his eyes during an interview with Mathias Doepfner, CEO of technology and media company Axel Springer. Musk was responding to the fact that Tesla is worth more than five times as much as Volkswagen, the world’s largest automaker in terms of sales.

Doepfner asked if Musk would consider using Tesla’s lofty stock price to buy an established automaker and although Musk said he’s not looking to do that, he wouldn’t rule it out.

“We’re definitely not going to launch a hostile takeover,” he said. “If somebody said, ‘Hey, we think it’d be a good idea to merge with Tesla,’ we’d certainly have that conversation.”