Companies are often publicly traded on major exchanges such as the NYSE, NASDAQ and AMEX. Every company that issues stock for trading has authorized, issued and outstanding shares. The number of shares authorized is usually established when the company first incorporates; however, the number may increase over time. Likewise, the amount of issued shares and outstanding shares may also change. You may obtain information about these values from corporate quarterly and annual regulatory filings. You may also calculate them if you know at least two key values.
Determine the number of shares authorized. The number of shares authorized is equal to the number allowed by the secretary of state in the state where the company is incorporated. Corporations usually request a larger amount of shares than they plan to issue so they don't have to reapply on a frequent basis. If you know the number of shares issued and unissued, or those authorized but not sold to shareholders, you can calculate authorized shares: shares authorized = shares issued + shares unissued.
Find the number of shares issued. The number of shares issued is typically significantly less than the number of shares authorized; the number of shares issued is also equal to the number of shares that were sold by the company or currently owned by shareholders. If you know the number of treasury stock, or shares reclaimed by the company but not retired, and the number of shares outstanding, you can calculate shares issued: shares issued = shares outstanding + treasury stock.
Calculate the number of shares outstanding. This is equal to the number of shares that a company has issued but not reacquired. This number is always less than or equal to the number of shares issued. Shares outstanding may also be found on any exchange where the company's stock is traded, listed as "shares out." The number of shares outstanding = number issued - treasury stock.