Actuarial Notes

Net Present Value

Study guide: Exam FM-2

The net present value (NPV) is the sum of the present values of all cash flows associated with a project or investment, with inflows treated as positive and outflows as negative. Discounting each cash flow C_t at effective rate i using v = (1+i)^{-1}:

NPV = \sum_t C_t\, v^t

= PV(\text{inflows}) - PV(\text{outflows})

  • A positive NPV means the investment creates value at rate i — the inflows more than compensate for the outflows at the chosen discount rate.
  • A negative NPV means the opposite.
  • The internal rate of return (IRR) is the rate i^* at which NPV = 0.

Comparing Two Investment Projects Project A requires an outlay of $10{,}000 today and returns $4{,}000 at the end of each of the next 3 years. Project B requires $10{,}000 today and returns $12{,}500 at the end of year 3 only. Using i = 6\%, which project has the higher NPV?

Answer Project A: NPV_A = -10{,}000 + 4{,}000\,a_{\overline{3}|0.06} a_{\overline{3}|} = \frac{1-(1.06)^{-3}}{0.06} = \frac{1-0.83962}{0.06} \approx 2.6730 NPV_A = -10{,}000 + 4{,}000 \times 2.6730 \approx -10{,}000 + 10{,}692 = \$692

Project B: NPV_B = -10{,}000 + 12{,}500\,(1.06)^{-3} = -10{,}000 + 12{,}500 \times 0.83962 \approx -10{,}000 + 10{,}495 = \$495

Project A has the higher NPV ($692 > \$495), so Project A is preferred at a 6% discount rate.