Net return on investment = $50,000 selling price – $20,000 cost = $30,000 return ROI = $30,000 return / $20,000 cost x 100 = 150% The ROI on this antique car is 150%.

If you try to calculate its annual return by dividing its simple return by five, you'd get the wrong answer. (3,100% / 5 = 620%, not 100%.) ...