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Market Capitalisation

In a stock market, all stocks are not same. Therefore, if you want to invest in stocks, you may want to select the right stocks that align with your investment goal. In choosing the best stocks to invest in, investors typically look at some metrics to better understand a stock. Market capitalization is one of those metrics investors commonly used to evaluate stocks. Market capitalization, also known as market cap, is the total market value of all outstanding shares of a company or stock. Therefore, market capitalization shows us the total value that investors have placed on a company’s shares.

How do you calculate market capitalization?

To calculate a company’s market capitalization, you multiply the number of the companys outstanding shares by its current stock price.


  1. A company with 50 million outstanding shares trading at $20 each would have a market cap of $1.0 billion.
  2. A company with 10 million shares trading at $200 each would have a market cap of $2 billion.

In the stock market, market capitalization can be used to categorize companies by size, as part of stock investing due diligence. There is no single rule in categorizing companies by market cap, so the list can be long or short. However, here are the common market cap tiers:

  1. Large-cap companies: These are typically large corporations with a market capitalization of $10 billion or more. Most large-cap companies have been around for many years, run strong brands, and operate in well-established industries where they are the major players. You can call the blue chip companies. Large-cap companies tend to be slow-growth businesses that may not deliver huge returns over a short period. However, they generally produce beautiful returns over a long-term and are deemed low-risk investment.
  2. Mid-cap companies: These are businesses with a market capitalization anywhere between $2 billion and $10 billion. Mid-cap companies are established businesses that have not yet realized their full growth potential. Therefore, mid-cap companies tend to have faster growth than large-cap companies. However, they are deemed higher risk investments than large-cap companies.
  3. Small-cap companies: These are businesses with market capitalization between $300 million and $2 billion. They are typically young companies with great growth potential. Small-cap stocks are deemed riskier investments than mid-cap and large-cap stocks, in part because they tend to have limited resources. Consequently, they are more vulnerable to economic downturn.

Applying market capitalization in risk assessment

As you can see, market capitalization can be a helpful metric for assessing the risks in a potential stock investment. Other market capitalization tiers you may come across are mega-cap and micro-cap, which sit at the extreme ends of the tiers we have examined above.

What causes changes in market capitalization?

A company’s market capitalization can change from time to time. A variety of factors can alter a company’s market cap. Here are two main factors that could cause a company’s market capitalization to change.

  • A Significant rise or drop in a company’s stock price. A company’s stock price can register a big move upward after the company reports strong earnings or releases a new product that investors believe will be a huge success. But the stock price can plunge if the company posts surprisingly weak earnings results or hit with a potentially costly lawsuit. Since market cap is tied to stock price, it would change accordingly.
  • An Increase or decrease in the number of a company’s outstanding shares. A company’s outstanding shares would increase if the company sells more shares, possibly to raise more capital to fund its expansion. Outstanding shares would decrease if the company repurchases some of its shares, a process that puts money back in the pockets of shareholders. Similarly, since market capitalization is tied to outstanding share count, it would change accordingly.

Although a stock split or reverse-split would change a company’s outstanding share count, they have no effect on market capitalization.

Bottom line

Market capitalization helps investors understand more about a company than they would if they just looked at the company’s stock price alone.

About the author

Harry Atkins
Harry joined us in 2019 to lead our Editorial Team. Drawing on more than a decade writing, editing and managing high-profile content for blue chip companies, Harry’s considerable experience in the finance sector encompasses work for high street and investment banks, insurance companies and trading platforms.

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