In the case of stock-based investments, there are two types of yields that are commonly used. When the yield is calculated based on the purchase price, it is known as the yield on cost (YOC) or cost yield, and it is calculated as follows: Cost Yield = (Price Increase + Dividends Paid) / Purchase Price. An investor could be considered successful if he or she realized a profit of $20 ($120 - $100) through a price increase and also received $2 from a dividend paid by the company. Thus, the cost yield is equal to ($20 + $2) / $100 = 0.22, or 22 percent of the total cost. Despite the fact that most investors prefer to calculate yields using market prices rather than purchase prices, there are others who use the purchase price as a basis for their calculations. The current yield can be calculated using the following formula: Current Yield = (Price Increase + Dividend Paid) / Current Price. The current yield is equal to ($20 + $2) / $120 = 0.1833 or 18.33 percent, based on the current price. As a result of the inverse relationship between yield and stock price, when the value of a company's stock increases, the current yield decreases.