Time Value of Money

The Starting Point NPV analysis allows us to compare monetary amounts that differ in timing. We can also incorporate risk into the analysis, however we will not concern ourselves with this complication at this time. Two items need to be determined before you start the NPV analysis, future cash flows and interest rates. Forecasting these is often more an art than a science, however in many situations these are either known or can be estimated.

Items needed to solve these problems You will need to know all but one of the following: interest ratei # of periodsn future valueFV present valuePV cash flowPMT

Methods to solve the problems A decent business calculator (e.g., HP10BII) A formula Tables A spreadsheet package (e.g., excel)

The following are useful formulas Future value of a single sum FV = PV * (1+i)**n Present value of a single sum PV = FV * 1/(1+i)**n

Simple versus compound interest Simple interest involves computing interest only on the original principal, not on any accrued interest. Compound interest involves calculating interest on interest.

Future Value – Simple Interest Example 1 Invest $1 for 3 12% per annum. PeriodBeg. Amt.InterestEnd. Amt

Future Value – Compound Interest Example 2 PeriodBeg. Amt. Interest End. Amt Formula ** ** **3 n =3, i = 12, PV = 1, FV = ?

Future Value Example 3 Invest $5 at the end of each year for 4 12%. What is the FV? now x 1.00 = x 1.12 = x = x = This is the same as the future value of an ordinary annuity n =5, i = 12, Pmt = 5, FV = ?

Present Value In each of the cases so far we wished to determine what a dollar would be worth in the future. We can also go the other direction. Often we wish to know what future sums are worth today. This is called present value (PV)

Present Value Example 4 What is the PV of a 10 dollars received 1 year from today assuming 12% interest? ? $10 Now 1 Note that $8.93 grows to $10 in 1 12% 8.93 x 1.12 = 10 n =1, i = 12, V = FV, PV = ?

Present Value Example 5 What is the PV of $4 received 3 years from today and $4 received 2 and 1 year from today at 5% interest? Now x.9524 = x.9070 = x.8638 = n =3, i = 5, PMT = 4, PV = ?

Non- Annual Periods So far we have computed FV of a single sum and an annuity and also PV of a single sum and an annuity. Each are basically the reverse of the other. Each has been computed with one compounding period per year. Often the compounding period is shorter.

Future values with non-annual deposits Example 6 What is the FV of a $75,000 deposit made every 6 months for 3 years using an annual rate of 10%? [((1.05**6)-1)/.05] x 75, x 75,000 = 510,143 n=6, i = 10, pmt = 75,000, FV = ? Note: Be sure to set your calculator to 2 payments per year.

Other Items to Solve For N = how long will it take a sum to grow to a certain FV at a given interest rate i = what interest rate is required to grow a certain sum to a given FV in a given length of time PMT = what payment is required to pay off a loan at a given interest rate in a set amount of time

Solving for n Example 7 How many periods does it take for $130 to grow to 15% per annum? n = ?, i = 15, PV = 130, FV =

Solving for i Example 8 At what annual interest rate will $175 grow to $ in ten years? n = 10, i = ?, PV = 175, FV =

Find the required payment Example 9 Compute the required semi-annual payment in order to have $14,000 at the end of 5 8% 14, x x x x x x x x x x n=10, i=8, PMT = ?, FV = -14,000

Car payments Example 10 What would be your monthly car payment on a $15,000 4 year 10%. Payments are made at the end of each month. PV = 15,000 n = 48 i = 10%; pmt =

Car payment Example 10 (continued) Instead of a 4 year loan, compute the payment for a 5 year (60 payment) loan. PV = 15,000 n = 60 i = 10%; pmt =

Car payment Example 10 (continued) Leave the loan at 5 years, but lower the interest rate to 8%. Compute the payment. PV = 15,000 n = 60 i = 8%; pmt =

Car payment Example 10 (continued) With the 5 year, 8 % loan, assume the maximum payment you can afford is $275. How much of a loan can you afford? n = 60 i = 8% pmt = 275; PV =

Car payment Example 10 (continued) Go back to the $15,000, 5 year, 10% loan. How much of the 12 th payment applies toward principal? Interest? What is the remaining balance? Do the same for the 36 th payment? Do the same for the 13 th – 24 th payments combined?

Present Value of an Annuity Example 11 You win a $4,000,000 lottery that pays $200,000 per year for 20 years. What is the present value of the lottery assuming a rate of 10%? n = 20, i = 10, PMT = 200,000; PV =

Uneven cash flows Up to this point we have assumed cash flows are the same each period. This is common for mortgage and lease payments. Things are not nearly as tidy when you need to determine if a project makes financial sense. Typically you will experience cash flows from revenues and expenses that vary each period.

Uneven cash flows This is the situation firms face when attempting to decide if a new location makes economic sense. Luckily this situation can still be handled with your financial calculator. You will be using a few new keys: CFj, Nj, IRR/YR, and NPV

Internal rate of return IRR/YR is used to compute the internal rate of return. This represents the interest rate that the project is earning over its life. This is similar to solving for i in the previous problems.

Net present value Sometimes you may know that you need a minimum return (internal rate of return) to take on a new location. You can then use this interest rate in the calculation and then compute the present value of all the combined cash flows. The summary number is the net present value of the project. If the project is earning a return greater the the required IRR, the NPV will be positive, otherwise it will be negative.

IRR and NPV example Example 16 You wish to determine the IRR and NPV of a project with the following projected cash flows: At inception: -10,000 End of year 1: 3,000 End of year 2: 1,000 End of year 3: 3,000 End of year 4: 8,000 Determine the IRR and then the NPV if the required return is 15%

Tips 1.Draw time lines 2.Put in all the knowns 3.Be sure to use the period interest rate 4.Make sure the answer passes the smell test (e.g., is the present value < the future value?)