What happened

One day after getting a boost from a positive analyst note out of Jefferies & Co., shares of Tesla (NASDAQ:TSLA) are revving once again, up 4% in 3:30 p.m. EDT Thursday trading.

With no new news about Tesla per se out on the wires, today, I think you have to credit today's stock price explosion to new Tesla rival Xpeng (NYSE:XPEV).

Rising red stock arrow representing a stock going up drawn on a yellow background.

Image source: Getty Images.

So what

Xpeng, as my Foolish colleague John Rosevear explained today, is the newest IPO in the electric-cars space, having just raised $1.5 billion selling 100 million American depositary shares (ADSs) at $15 apiece on the NYSE -- a result that Barron's calls "really, really" good.  

Now what

And here's the thing: Xpeng won this valuation despite having no profits whatsoever. (To the contrary, John says Xpeng lost about half-a-billion dollars last year and is continuing to lose about $200 million every six months today). Yet despite this lack of profits, S&P Global Market Intelligence puts the Chinese electric-vehicle maker's valuation at a cool $10.2 billion -- or about 34 times trailing-12-month sales of $303.5 million.

Now, if Xpeng is worth 34 times sales without profits, but Tesla shares are selling for less than 15 times sales with profits, does this perhaps mean that, despite a market valuation now approaching $420 billion, Tesla stock is actually still undervalued?

That seems to be the thinking on Wall Street today, which would explain why Tesla stock is still going up.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.