While stocks can be valued in a number of ways, essentially the value of a stock is what someone is willing to pay for it. As such, the value of a stock is determined by the market itself, such as can be seen in public stock markets or exchanges. In the case of private equity or a private company, the value of a stock is established by the company itself and is usually based on either income or capitalization. Stocks are considered ''Overvalued'' if their high price is a result of high buying volumes more than underlying profitablity, and ''Undervalued'' if they have strong potential fundamentals but investor demand for it is weak.
In the case of income-based valuation of stock, the value of the stock is established by the income of the company. The income of the company is treated as the return on investment, the investment being the full value of the company. The value of the company is divided by the number of shares the company wishes to issue and the value of the stock is the product of that calculation. Alternatively, the value of a stock may also be issued on the basis of market capitalization.