Lock up all domestic terrorists

If Elon Musk only owns 14%.of Tesla, who owns the other 86%?

This is easily looked up if you have a computer or cell phone.
4,740 various state pension funds via ETFs and mutual funds, and other institutions. Elon actually owns 12.8% as of 2/28/2025.

Wait, so Musk isn't majority stockholder? Risky if you ask me.

Very common.
Zuck only owns 13.5% of Facebook.
Bezos only owns 9% of Amazon.
Warren Buffet owns less than 2% of Berkshire Hathaway.
Bill Gates owns 1.34% of Microsoft.

The founders of most large companies own just a tiny fraction of the shares outstanding.

They got rich by selling shares of stock in their companies to large institutional investors, not from owning the company itself.