In finance, rate of return (ROR) is the ratio of money gained or lost on an investment relative to the amount of money invested. This amount of money gained or lost may be referred to as interest, profit/loss, gain/loss, or net income/loss. The money invested may be referred to as the asset, capital, principal, or the cost basis of the investment. ROI is usually expressed as a percentage rather than a fraction. Investments generate cash flow to the investor to compensate the investor for the time value of money. The main factors that are used by investors to determine the rate of return at which they are willing to invest money include estimates of future inflation rates, estimates regarding the risk of the investment and whether or not the investors want the money available ("liquid") for other uses. This new book gathers the latest research from around the world on this topic.