Can you own a
rocket company?

Imagine you and some friends start a lemonade stand. You all help build it, so you cut its ownership into ten equal pieces. Each little piece is a share.

If you own one share, you own one-tenth of the stand. If it becomes successful, your piece may become more valuable. You might receive some profit, or the owners might use that money to buy a bigger juicer and open another stand.

A share price is what buyers and sellers agree on today. They are all making guesses about how useful and profitable the company could be in the future.

This model is deliberately simple. Real prices are affected by profits, interest rates, news, fear, excitement and many other forces.

SpaceX is an unusually ambitious business. It launches rockets, operates the Starlink satellite network and is working toward missions far beyond Earth. Those projects could create enormous value—but they also cost enormous amounts of money and can fail.

Buying one share has an uneven range of possible results. The loss has a floor, while the potential gain does not have a fixed ceiling.

That does not mean the good outcome is likely. A possible 10× gain can still be a bad choice if the chance of success is tiny. Smart decisions consider both the size of an outcome and its probability.

In a capitalist economy, owning shares in productive companies is one way savings can grow over many years. But putting everything into one exciting company can be dangerous.