Wall Street hit the brakes on Uber Friday — despite vows from chief executive Dara Khosrowshahi that its record $5 billion loss, reported late Thursday, will never happen again.

After dropping more than 6% in late trading Thursday, Uber’s stock went on a daylong slide Friday that saw it close down 6.8% at $40.05.

Khosrowshahi tried to calm investors by calling the loss a “once-in-a-lifetime” hit tied to stock-based payouts to workers and shareholders following its May initial public offering.

In an interview with CNBC, Khosrowshahi said he expects Uber’s business to be “very profitable” when it reaches maturity, though he did not give any indication of when that might be.

Wall Street remains unconvinced.

“The more Uber makes, the more Uber loses,” San Francisco-based tech analyst Beth Kindig told The Post. “What needs to turn around are the net losses. They’re growing as revenue grows, and that’s the exact opposite of what a successful company has in their financials.”

“We have no evidence that Uber can be profitable,” she added. “In fact, we have more evidence that it may be impossible to be profitable.”

Uber Thursday reported it lost $4.72 a share in the second quarter on revenue of $3.17 billion. Wall Street had been expecting a loss of $3.12 a share on revenue of $3.36 billion.

Khosrowshahi on Friday also took a swipe at New York City’s Taxi and Limousine Commission, which recently voted to extend the freeze on new for-hire vehicles in the Big Apple another year.

He called the decision “a tragedy” and accused the TLC of hurting low-income New Yorkers by forcing Uber to raise its prices.

“What is happening in New York is there is a secondary medallion system being created with this limit on the number of drivers and on the number of cars,” Khosrowshahi told CNBC. “And we know that the first medallion system ended in tears. And now we’re doing it again.”

Reached for comment by The Post, the TLC called Khosrowshahi’s comparison “incredibly misleading and just patently inaccurate.”

“Uber should just ask its own drivers whether the analogy makes sense, especially when one out of five choose not to renew their vehicle licenses at renewal time,” deputy commissioner for public affairs Allan Fromberg said.

“The fact is, these new regulations are a victory for drivers, passengers and really everyone who wants to live in a greener, healthier and less congested city,” Fromberg added.