Cost of Capital

Cost of capital is the price an organization pays for the money it uses. Lenders expect interest, and shareholders expect a return that compensates them for the risk of owning the business. The cost of capital combines these expectations into a single rate, which represents the minimum return any investment must earn to create value. An investment that returns less than the cost of capital destroys value, even if it appears profitable on its own.

The cost of capital is used throughout corporate finance, most visibly as the discount rate for evaluating investments. For technology leaders, it matters because every major technology investment, from a data center to a new platform, competes for capital with other uses across the business. Understanding the cost of capital helps IT leaders build business cases that finance teams accept and explains why some projects with positive returns are still rejected.

Definition of Cost of Capital

The cost of capital is the rate of return a company must earn on its investments to maintain its market value and satisfy its providers of capital. It reflects both the time value of money and the risk of the investment.

Most organizations calculate it as the weighted average cost of capital (WACC), which blends the cost of debt and the cost of equity according to the proportion of each in the company's financing.

Cost of Debt and Cost of Equity

The cost of debt is the interest rate the company pays on its borrowing, adjusted for tax, since interest is usually tax-deductible. If a company borrows at 6 percent and its tax rate is 25 percent, its after-tax cost of debt is 4.5 percent.

The cost of equity is the return shareholders expect. It cannot be observed directly, so it is usually estimated using models such as the capital asset pricing model, which adds a premium for the company's risk to a risk-free interest rate. The cost of equity is normally higher than the cost of debt, because shareholders bear more risk than lenders.

Both components change over time as interest rates, market conditions and the company's own risk profile change, so the cost of capital is typically updated at least once a year.

Weighted Average Cost of Capital

WACC weights the cost of each source of capital by its share of total financing. A company financed 30 percent by debt with an after-tax cost of 4.5 percent, and 70 percent by equity with a cost of 11 percent, has a WACC of about 9 percent.

Many organizations set a hurdle rate for investments at or above their WACC. Riskier projects may be assigned a higher rate to reflect their additional uncertainty.

Finance teams usually provide the WACC or hurdle rate for business cases, so IT teams do not need to calculate it themselves, but understanding where it comes from helps when discussing results.

Importance of Cost of Capital in IT Financial Management

Technology investments often involve large upfront costs and benefits spread over several years. The cost of capital determines how those future benefits are valued today, and therefore whether the investment is worthwhile.

It also shapes comparisons between owning and renting technology.

Because many organizations have limited capital, the cost of capital also acts as a filter, determining which technology projects compete successfully for funding.

Evaluating Technology Investments

In capital budgeting, future cash flows are discounted at the cost of capital to calculate net present value. A higher cost of capital reduces the present value of future benefits, making long-term investments harder to justify.

For example, a platform that saves $1 million a year for five years is worth about $3.99 million today at an 8 percent discount rate, but only about $3.6 million at 12 percent. A project costing $3.8 million would be approved at the lower rate and rejected at the higher one.

This sensitivity is why technology business cases should state the discount rate used and, where relevant, show results at different rates.

Own vs Rent Decisions

Buying hardware or perpetual licenses ties up capital upfront, while cloud services and subscriptions spread costs over time. The cost of capital determines how much value the organization places on keeping capital free for other uses.

When the cost of capital is high, paying over time becomes more attractive relative to buying upfront, all else being equal. Comparisons of capex vs opex options should discount cash flows at the cost of capital rather than simply adding up costs.

Interest rate changes therefore affect technology sourcing decisions. Periods of high rates tend to favor subscription and consumption models, while periods of low rates make ownership relatively more attractive.