Actuarial Notes

Current Value

Study guide: Exam FM-2

The current value of a cash flow stream is its value at a specified reference date t — not necessarily today (present) or at the end (future). It is computed by accumulating the cash flows that occur before t and discounting those that occur on or after t to the reference date, using the applicable Interest Rate or Accumulation Function. When every cash flow is discounted it is the Present Value; when every one is accumulated, the Future Value.

\text{CV}_t = \sum_{k} C_k \cdot \frac{a(t)}{a(t_k)}

  • a(t) is the Accumulation Function and C_k is the cash flow at time t_k; the ratio accumulates a cash flow with t_k < t and discounts one with t_k > t.
  • This form holds under Compound Interest, a force of interest, or any accumulation function a question gives other than simple interest. Under compound interest at rate i:

\text{CV}_t = \sum_{k} C_k\,(1+i)^{t - t_k}

  • Simple Interest is the exception. When a question specifies simple interest, SOA starts each cash flow's simple interest on its own date, so a cash flow before t grows by 1 + i(t - t_k) and one on or after t is divided by 1 + i(t_k - t) — it is not moved by a(t)/a(t_k) with a(t) = 1 + it:

\begin{aligned} \text{CV}_t = {} & \sum_{t_k < t} C_k \bigl[1 + i(t - t_k)\bigr] \\ & + \sum_{t_k \geq t} \frac{C_k}{1 + i(t_k - t)} \end{aligned}

Value at an Intermediate Date Payments of 1000 at time 0 and 1000 at time 4 are made. Find the current value at time 2 using an effective annual rate of 5%.

Answer Accumulate the time-0 payment forward 2 years and discount the time-4 payment back 2 years: \text{CV}_2 = 1000(1.05)^2 + 1000(1.05)^{-2} = 1102.50 + 907.03 = 2009.53