Why Rocket Lab Stock Rocketed Higher Today

Rocket Lab (NASDAQ: RKLB) stock soared to close up 10.4% on Thursday, despite having to abort a planned rocket launch yesterday to "assess sensor data."

The most likely reason for the shares rising in the face of, at best, neutral news on the business: Rocket Lab archrival SpaceX, already the biggest space company on the planet, is planning to get even bigger.

Potentially, $1.5 trillion big.

Because SpaceX will IPO in 2026.

SpaceX versus Rocket Lab

What does this have to do with Rocket Lab? The connection isn't obvious, but a lot of investors (especially on "X") are trying to make it anyway. Here's one illustrative post:

SpaceX valuation: $1.5T

SpaceX expected 2026 sales: $23B

SpaceX Forward Value/Sales = 65X

Rocket lab valuation: $28.5B

Rocket lab expected 2026 sales: $900M

Rocket lab Forward Value/Sales = 32X$RKLB 👀 pic.twitter.com/aWJSCrYmcz

-- Hartik (@Hartik__) December 9, 2025

So, the logic seems to be that if SpaceX IPOs at a valuation of 65 times its expected 2026 sales, but Rocket Lab stock has a price-to-sales ratio only half that -- 32x -- then, obviously, Rocket Lab stock is going to double in price.

Is Rocket Lab stock a buy?

There are at least a couple problems with that logic, though. First and most obviously, if it turns out that SpaceX stock is overvalued (and I would argue a $1.5 trillion valuation does overvalue SpaceX), then it doesn't logically follow that Rocket Lab stock will double at all. In fact, it might even fall.

The other issue I have with this thinking is that SpaceX and Rocket Lab are not equivalent companies. First and most obviously, because SpaceX is a profitable space business, and Rocket Lab isn't (at least not yet).

This isn't to say Rocket Lab isn't worth twice its present share price of $63 and change, of course. I just don't believe the case is quite as cut-and-dried that Rocket Lab is worth twice as much, as a lot of investors on social media seem to think it is.

Rich Smith has positions in Rocket Lab. The Motley Fool has positions in and recommends Rocket Lab. The Motley Fool has a disclosure policy.