Tesla stock was down early Wednesday, falling with SpaceX.hares. The two stocks have become linked, by more than just Elon Musk, who runs both companies.

Shares of the EV maker were down 0.7%% at $324.94 in early trading, while the S&P 500 and Dow Jones Industrial Average were up 0.5% and 0.7%, respectively.

SpaceX stock was down 10.3% at $112.33 after reporting second-quarter earnings. Numbers don't seem to be the issue. SpaceX reported better-than-expected sales and earnings. The stock rose almost 16% on Monday and Tuesday, ahead of earnings. Early prices still leave SpaceX stock up about $3 for the week.

That is the pattern for Tesla stock, too. Coming into Wednesday trading, shares were up about 5% for the week following gains on Monday and Tuesday.

Tesla and SpaceX, of course, have a lot in common. There is CEO Elon Musk. What's more, both are investing heavily in AI, and they are working together on AI applications and a semiconductor manufacturing facility.

SpaceX is spending tens of billions to build AI data center capacity as quickly as possible. AI CapEx in the quarter was $15.8 billion, up from $749 million a year ago. SpaceX's AI compute capacity rose to 1.4 gigawatts, up from 0.4 gigawatts a year earlier.

Tesla spent $5.8 billion on new plants and equipment in the second quarter, up from $2.4 billion in the second quarter of 2025. Its AI compute capacity "more than doubled in the first half of 2026."

Tesla is using that capacity to train cars to drive themselves, among other things. SpaceX is renting out its capacity to Anthropic and Google while also developing its Grok AI models.

The AI focus is why more than a few Wall Street analysts see a merger between the two as inevitable. This past week, Musk had to tamp down speculation that Tesla would sell its Chinese operation to help facilitate a merger with SpaceX. Theoretically, the move would smooth the process by removing regulatory hurdles such as Chinese deal approval and the U.S. government becoming comfortable with a defense supplier, SpaceX, doing a lot of business in China.

It would be a costly move. Tesla generates roughly 20% of annual sales in that country. Tesla sold 93,579 vehicles from its China plant in July, up 38% year over year, according to the China Passenger Car Association. That is a wholesale number, including exports. It's the ninth consecutive year-over-year gain.

A merger, if it happens, is likely more than a year away. Investors can worry more about Tesla's results, such as car production in China, for a little while.

Tesla was mentioned once on SpaceX's earnings conference call. "I'd say probably outside of China, SpaceX and Tesla are the two best companies on Earth at hardware, and I think perhaps even including China," said Musk.

Comments like that will only fuel merger speculation.