Electric truck maker Nikola (NKLA) may have gotten off to a hot start by more than doubling after becoming a publicly traded company this month, but it has yet to win over Shark Tank’s Barbara Corcoran.

On Thursday, Corcoran emphasized caution on the automaker that briefly saw its market cap swell beyond Ford’s this month, despite the company posting losses of nearly $200 million since its inception.

While the company has attracted comparisons to Elon Musk’s Tesla Motors, Corcoran said Nikola’s founder Trevor Milton may be a good salesman for bringing his company so much attention in such little time, but he has a ways to go to earn Musk’s credibility.

“I wouldn't put my money there,” she told Yahoo Finance’s YFi PM. “I'm a believer in Tesla, wholeheartedly. I don't feel the same way about Trevor. Here's what I give him: I give him great grades for being a phenomenal salesperson.”

Nikola, which was founded in 2014, hopes to have its first consumer electric truck dubbed the Badger delivered in the next two years. Milton told Yahoo Finance earlier this month that he hopes the Badger can begin its path to dethrone Ford’s sales-leading F-150 pickup truck when orders open June 29. Ford’s pickup has topped the category’s sales charts for 43 consecutive years.

Critics of Nikola have raised issue with the showmanship of Milton maybe going beyond what the company has delivered thus far. Bloomberg, for example, recently documented how Milton may have exaggerated at a 2016 showcase for its Nikola One semi-truck. At the time of the show, the truck was forecast to begin deliveries in 2020, but the company is now less comital about its timeline for the model and does not forecast revenue for it this year. Milton tweeted Wednesday that Nikola would be taking legal action against Bloomberg for what the company claimed was an “intentionally misleading story.”

To be fair, Tesla also once suffered criticism for shifting timelines and profitless quarter after profitless quarter. It took the Musk-led company more than a decade to go from founding to delivering its first mass production consumer model with its Model 3 in 2017, following its higher-end Roadster and Model S. Since then, however, Tesla has proven itself with real profits and real growth — something Corcoran says Nikola and Milton will have to show progress on quickly to justify its high-flying price.

“He lacks credibility because he’s not giving any clarity on when it's going to be delivered,” Corcoran said. “And you're declaring war on the most successful truck in the industry.”

For his part, Milton took Corcoran’s criticism in stride Thursday, noting that he has “some work to do” to win over the Shark Tank host.

Zack Guzman is the host of YFi PM as well as a senior writer and on-air reporter covering entrepreneurship, cannabis, startups, and breaking news at Yahoo Finance. Follow him on Twitter @zGuz.

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