Question 5.7: The Opportunity Cost of Capital Suppose a friend offers to b...
The Opportunity Cost of Capital
Suppose a friend offers to borrow $100 from you today and in return pay you $110 one year from today. Looking in the market for other options for investing the $100, you find your best alternative option that you view as equally risky as lending it to your friend. That option has an expected return of 8%. What should you do?
Plan
Your decision depends on what the opportunity cost is of lending your money to your friend. If you lend her the $100, then you cannot invest it in the alternative with an 8% expected return. Thus, by making the loan, you are giving up the opportunity to invest for an 8% expected return. You can make your decision by using your 8% opportunity cost of capital to value the $110 in one year.
Execute
The value of the $110 in one year is its present value, discounted at 8%:
The $100 loan is worth $101.85 to you today, so you make the loan.
Evaluate
The Valuation Principle tells us that we can determine the value of an investment by using market prices to value the benefits net of the costs. As this example shows, market prices determine what our best alternative opportunities are, so that we can decide whether an investment is worth the cost.