Tesla bulls and shorts debate BYD. One says it’s complementary, the other says it’s a threat.

On a TV show Thursday, Tesla investor Ross Gerber and Gordon Johnson, the stock's most bearish analyst, took center stage to offer sharply different views of the electric car giant and engage in a heated debate over whether Tesla's biggest rival, BYD, should enter the U.S. market.

Ross Gerber is the CEO of Gerber Kawasaki Wealth Management and holds a stake in Tesla worth about $100 million. "I think BYD is a very successful company, probably one of the best companies in China... but it's not a threat to Tesla," he said.

Gerber believes that the two companies do not pose a threat to each other. Their common enemies are traditional car manufacturers such as Ford, BMW, and Volkswagen.

"I think they're very complementary companies," Gerber said. "They're very similar in many ways and both are great companies."

But Johnson disagreed with Gerber, who is the CEO of GLJ Research and has predicted that Tesla's stock price will fall to $23.

"What's happening now is that consumers... are moving away from Tesla," the Tesla short said, adding that Tesla's cars are unreliable and unsafe.

The two analysts not only have different views on Tesla, but also on the Chinese electric car maker. Gerber thinks BYD must be allowed into the U.S. market and allowed to compete with Tesla and other companies, while Johnson thinks it shouldn't be.

According to Gerber, if BYD enters the U.S. market, the biggest challenge will be U.S. consumers' reluctance to buy Chinese-made cars.

Johnson believes that allowing Chinese electric car manufacturers who enjoy cheaper labor and energy to enter the U.S. market is unfair to U.S. automakers and is not a level playing field.

The debate between the two analysts comes as competition between BYD and Tesla intensifies as the end of the year approaches. Current market predictions are that BYD will replace Tesla as the world's best-selling pure electric vehicle manufacturer in the fourth quarter.

In the third quarter of this year, BYD's pure electric vehicle shipments were approximately 432,000 units, slightly lower than Tesla's 435,000 units.