What is market cap?

A company has 500 million shares that trade at $40 each. Its market cap is 500 million × $40 = $20 billion.

A second company's shares trade at $400, but it has only 10 million of them, so its market cap is $4 billion. The second company has the higher share price but is the smaller company: the share price alone does not tell you how big a company is.

On JagSim's Research page, Compare shows companies side by side. On Pro it compares up to 5 companies across 27 figures, and market cap is one of them, worked out from today's price and the share count in the company's newest report. Free members compare the price moves of 2 companies on one chart.

Market cap is the usual way to sort companies by size. Size tends to go with how a stock behaves: very large companies are often steadier, and small ones can move further in a day. It is also how most big indexes, such as the S&P 500, decide how much each company counts.

How is market cap calculated?

Share price times the number of shares outstanding. 500 million shares at $40 is a $20 billion market cap.

What do large cap, mid cap and small cap mean?

Rough size bands. A common split in the US is large cap at about $10 billion and up, mid cap from about $2 billion to $10 billion, and small cap from about $300 million to $2 billion. Index providers draw the lines a little differently.

Does a higher share price mean a bigger company?

No. A $400 stock can be a smaller company than a $40 stock if it has far fewer shares. Compare market caps, not share prices.

Why does market cap change every day?

Because the share price changes with every trade. The number of shares changes far less often, when a company issues new shares or buys some back.