It Took SpaceX Just 1 Day to Reach a Milestone Tesla Has Never Achieved. Which Elon Musk-Led Stock Is the Better Buy in June?

Shares of Tesla (NASDAQ: TSLA) reached their all-time intraday peak of $498.83 on Dec. 22, 2025, giving it a market cap of around $1.67 trillion.

On June 12, Space Exploration Technologies (NASDAQ: SPCX), more widely known as SpaceX, held its initial public offering and closed the session with a market cap of $2.11 trillion.

Here's why SpaceX is soaring, and which growth stock is the better buy now.

Image source: Getty Images.

Private investors hold the majority of SpaceX's value

SpaceX raised $75 billion by selling 555.6 million shares at a price per share of $135. The float, which is the shares available for public trading, is less than 5% of the shares outstanding, meaning the vast majority of SpaceX is still owned by insiders who were awarded shares as compensation or institutions that bought in during pre-IPO funding rounds. The float should increase gradually as SpaceX is allowing those insiders to sell some shares well before the usual 180-day lockup period ends.

With so much demand for shares and a relatively small available supply, SpaceX's valuation could continue to run up, at least in the short term. But those market dynamics could also inflate it with a lot of hot air, which could compress once the float makes up the majority of outstanding shares. Even with Elon Musk still owning around 19% of Tesla as of April, Tesla's float is now about 75% of the shares outstanding.

Tesla and SpaceX have sky-high valuations

A few years ago, Tesla was raking in free cash flow at margins that led the auto industry. But the electric vehicle (EV) market has since taken a hit. Consumer adoption of the technology has been slower than expected, and President Donald Trump's "big beautiful bill" removed the tax incentives that made EVs more affordable, putting another headwind on demand. Tesla's first-quarter deliveries were up just 6.3% year over year, while its energy storage product deployments fell 15.4%.

Aggressive investments in its efforts to build a robotaxi network, enhance its self-driving software, and develop marketable humanoid robots (Optimus), among other endeavors, are driving surging capital expenditures that are taking a sledgehammer to Tesla's profitability. The current consensus estimates among analysts is that it will earn just $2.06 per share in 2026, and $2.50 per share in 2027 on sales of $118.45 billion. That gives it a staggering forward price-to-earnings ratio of 162.4. For context, Tesla's all-time high annual EPS was $4.30 in 2023.

SpaceX's valuation is even more lofty. In 2025, its revenue increased by 33.2% to $18.67 billion, and net income went from $791 million in 2024 to a $4.94 billion net loss in 2025. With its market cap topping $2.5 trillion as of the close of trading Monday, that gives it a price-to-sales ratio of about 134 relative to its 2025 revenue.

When Tesla's earnings were soaring, it would have been the obvious choice over SpaceX for investors interested in companies offering proven profitability. But now, Tesla and SpaceX are both carrying values that depend far more on their anticipated growth potential than on what they are delivering today. So the answer to the question of which is the better buy may come down to which end markets you're more excited about.

Undeniable potential

Tesla's robotaxi network could end up being more valuable than its passenger vehicle business -- especially as legacy automakers and pure-play EV competitors continue to release more advanced models. Utility-scale energy storage is another massive growth market as the tech sector looks for ways to alleviate the artificial intelligence energy bottleneck. And while Tesla has talked extensively about using its Optimus robots in residential settings, the bigger opportunity may be in factory operations.

SpaceX's main revenue driver is its Starlink network of low-Earth-orbit satellites that provide broadband connectivity and wireless internet to commercial, governmental, and residential customers. SpaceX also works with government agencies and commercial customers to launch payloads into space using its reusable Falcon 9 booster.

It also owns xAI, the maker of the Grok large language models, and social media platform X. AI could be a key driver of SpaceX's near-term growth, including through the deployment of data centers in space as early as 2028.

SpaceX's Earth ambitions are bold, but they pale in comparison to the company's stated mission: "To build the systems and technologies necessary to make life multiplanetary, to understand the true nature of the universe, and to extend the light of consciousness to the stars."

A merger could be on the way

Investors may not need to choose between SpaceX and Tesla for long. I fully expect the companies to at least attempt to merge as soon as next year.

The current regulatory environment in the U.S. is extremely business-friendly, so if there were ever a time to propose such a megamerger, it would be now. What's more, both SpaceX and Tesla could benefit if CEO Musk were putting all of his efforts into one combined company rather than splitting his focus.

Tesla and xAI already collaborate on Tesla's Full Self-Driving technology, and xAI's Grok is integrated into Tesla vehicles and Optimus robots. Meanwhile, xAI buys energy storage systems from Tesla, and the companies are collaborating on a chip manufacturing initiative called Terafab.

To top it all off, Tesla was an early investor in xAI, which SpaceX merged with earlier this year. So the longer-term plan all along seems to have been to eventually unite all of Musk's companies under one umbrella.

The combined market cap of SpaceX and Tesla as of the close of trading Monday was about $4 trillion -- behind Nvidia, Alphabet, and Apple for the fourth-most-valuable company in the world.

The better buy

SpaceX has a big advantage over Tesla in that it has few real competitors, whereas Tesla faces mounting competition from other EV makers, automakers incorporating self-driving features into their vehicles, and pure-play autonomous vehicle rivals like Alphabet-owned Waymo.

However, even with more competition, Tesla has a much clearer path to consistent profitability if the adoption of its autonomous vehicles and robots grows. SpaceX, by contrast, still needs to prove it can expand without relying on the capital markets to raise money.

Daniel Foelber has positions in Nvidia. The Motley Fool has positions in and recommends Alphabet, Apple, Microsoft, Nvidia, and Tesla. The Motley Fool has a disclosure policy.