Every investor has had a thought from time to time that goes something like this: "If I had just bought that one stock early enough, I'd be rich now."

It's a tempting thought experiment to go back and calculate how buying Apple, Amazon, Microsoft, or other companies shortly after their initial public offerings (IPOs) could have changed your portfolio.

And some investors are likely thinking this way about Space Exploration Technologies (SPCX +7.36%) right now. After all, SpaceX has a leading artificial intelligence business, a successful rocket launch business, and a rapidly growing Starlink satellite internet company.

So, is SpaceX the stock that investors will look back on years from now and wonder if they had just put $5,000 toward it, they'd be a millionaire?

I think not, and here's why.

The math doesn't add up

SpaceX's share price is about $160 as of this writing. To turn a $5,000 investment into $1 million would require SpaceX's stock to increase by almost 20,000%. That's a nearly impossible feat and highly unlikely considering SpaceX's market cap is $2 trillion already.

Some investors are still optimistic that the company could experience significant share price gains, though. And there are a few legitimate reasons to be optimistic about SpaceX.

For one, the company has a thriving satellite internet business. SpaceX says Starlink has 12 million paid subscribers, with about 3 million of those residing in the U.S. The number of U.S.-based Starlink customers could reach an estimated 15 million in just four years, according to analysts at Oppenheimer.

Starlink accounts for around 60% of SpaceX's top line and is the company's only profitable business, with about $2.6 billion in EBITDA in the second quarter.

An expanding Starlink business could fuel momentum for SpaceX stock over the next several years if the company can continue to expand its user base. Just don't expect out-of-this-world returns for SpaceX stock because of Starlink.

Expand NASDAQ : SPCX Space Exploration Technologies Today's Change ( 7.36 %) $ 10.89 Current Price $ 158.96 Key Data Points Market Cap $2.2T Market cap calculated using publicly traded shares outstanding only. Does not include unlisted, private, or dual-class non-traded shares. Implied market cap may vary. Day's Range $ 149.34 - $ 159.84 52wk Range $ 104.83 - $ 225.64 Volume 509.6K Avg Vol 92.8M

SpaceX's spending spree is a problem for the stock

I think one of the biggest inhibitors to SpaceX's stock gains is the company's accelerating capex.

SpaceX spent $28.5 billion in the first six months of 2026, an increase of 309% from the first half of 2025. The vast majority of that was funneled into the company's artificial intelligence initiatives, including building large data centers.

The AI boom is well underway, and many investors have been pretty patient with all of the spending. But their patience is starting to run out for companies that aren't profitable, which SpaceX isn't.

If the company continues on its current capex path, I doubt SpaceX stock will make significant gains from its current level. There are simply too many other AI stocks to choose from that spend less and still deliver impressive profits for their shareholders.

All of which means that if you're on the fence for where to put $5,000 right now, SpaceX probably isn't your best bet -- and it certainly won't help make you a millionaire.