Cost of capital
The cost of capital is the return a firm must earn on an investment to satisfy those who provide its funds.
Money is never free. The return a firm must earn just to satisfy those who provide its funds, the cost of capital, is the hurdle every investment must clear.
The cost of capital is the return a firm must earn on its investments to satisfy the providers of its funds, both lenders and shareholders. It is the minimum acceptable return, the hurdle rate that an investment must clear to be worth making, and a central input to valuation and investment decisions.
The price of funds
A firm finances itself with money from two main sources, debt and equity, and each demands a return. Lenders require interest; shareholders require a return commensurate with the risk they bear. The cost of capital is the blended return these providers collectively require, the price the firm pays for the money it uses. Because the funds must be remunerated, any investment that earns less than this cost destroys value, returning too little to satisfy those who supplied the capital, while one earning more creates value.
Risk drives the cost
The cost of capital reflects risk. Riskier firms and projects must offer higher returns to attract funds, because investors demand compensation for bearing greater uncertainty, so a risky venture faces a higher cost of capital than a safe one. This is why the cost of capital is not a single universal number but specific to a firm and even to a project: the relevant cost is that appropriate to the risk of the particular investment being appraised, which is why applying a single company-wide rate to projects of differing risk can mislead.
Why it is the hurdle
The cost of capital functions as the hurdle rate in investment appraisal: the discount rate used to value future cash flows and the minimum return a project must beat. Set it too low and the firm accepts value-destroying projects that fail to cover the cost of their funds; set it too high and it rejects worthwhile ones. Because it determines which investments pass and what they are worth, estimating the cost of capital accurately, however difficult, is one of the most consequential tasks in corporate finance.
The cost of capital is the foundational hurdle of financial decision-making, the return a firm must earn simply to keep its investors whole. It anchors valuation as the discount rate and investment as the minimum acceptable return, and its dependence on risk means that getting it right, neither too generous nor too demanding, is essential to allocating capital well, since every project is ultimately judged by whether it earns more than the funds it consumes cost to obtain.