What is a stock?

A share of stock is a small piece of ownership in a company. If a company has 1 billion shares and you own 100, you own one ten-millionth of it: a tiny slice of its profits, its assets, and its future.

Companies sell shares to raise money to grow. After that first sale, shares trade between investors on stock exchanges. When you buy a share, you usually buy it from another investor, not from the company.