If I was looking to calculate the market capitalization of a company I need to find the number of shares that are outside the company and then multiply it by the share price Finding that number of shares is thus my job here So we start by looking at the preference shares or preferred stock Would I include them? No I would not, they are not voting shareholders Moreover, they receive a fixed dividend. They don't actually thus receive a share of the profits They're just getting a fixed share every year If I'm looking to buy the company, this is not what I'm looking to buy I'm not looking to buy the preference shares or preferred stock What about the authorized number of shares? Well this is just a theoretical figure (a maximum), the maximum number of shares that the board can issue If we look at Oracle's equity balance here, I can see right in the middle of it, it says "authorized: 11,000 shares" That is not the right figure at all What I'm actually looking for is the outstanding number of shares and again for oracle here, the outstanding number is 4,464 shares The balance sheet is sometimes a good place to go looking for the number of shares The footnotes also good. If you're an American company and you're looking at their annual report The front page of the annual report (called the 10-K) will give you the most up to date figure Unless they've issued quarterly reports, in which case the front page of that (the 10-Q) will be a good place You can alternatively try to calculate it. To do this, you take the number of shares that have been issued i.e. shares physically in existence I'm gonna make up a figure, let's say a company has ever issued 1,000 shares But you then need to subtract the number of treasury shares (the number of shares that have been bought back by the company) Maybe the company in my example has bought back 100 So the outstanding shares here would be the 1,000 issued minus the 100 treasury, would give me 900 outstanding shares