# 19

Dr. Kevin Bracker; Dr. Fang Lin; and jpursley

Most of TVM analysis on your Financial Calculator can be done with the 5-key approach. The five keys are as follows

N ⇒ This key refers to the number of periods

I/Y ⇒ This key refers to the interest rate (do not enter as a decimal ⇒ 10% would be 10 not 0.10). Sometimes this interest rate is referred to as a discount rate or rate of return.

PV ⇒ This key refers to the Present Value

PMT ⇒ This key refers to the Annuity Payment

FV ⇒ This key refers to the Future Value

When entering values into your financial calculator you press the value you are entering first, then the key. For example, if we want to put in 10 periods, we would enter this as 10 N. Sometimes you will need to enter a negative value. To do this, you must use the “+/-“ key on your calculator instead of the “–“ key. The order that you enter the variables doesn’t matter as long as you enter the four that you know first, and then solve for the fifth. To solve, you just press the Compute (CPT) key and then the key representing what you are trying to find. Now let’s go through several examples.

# EXAMPLE ONE – Future Value of a Single Cash Flow

You are investing $10,000 today and want to know how much you will have after 6 years if you earn a 7% rate of return over the 6-year time frame. Since you are starting with$10,000, that is your present value. You have 6 years, so the number of time periods is 6. The 7% rate of return means you have a 7% interest rate. In this example we are not using an annuity, so we are going to set the Annuity Payment to zero.

6 N
7 I/Y
10,000 PV
0 PMT
CPT FV     -15,007.30

# ANNUITIES

An annuity is a sequence of equal, periodic cash flows. Many financial situations can be modeled as an annuity. For instance, calculating a mortgage payment on a home is an annuity. Simple retirement analysis can be structured as an annuity. Also, bond valuation is partially modeled as an annuity since we receive a fixed coupon payment each year. With annuities, we assume cash flows come at the end of each period. Note that there is a variation referred to as an “Annuity Due” that assumes cash flows come at the BEGINNING of the period. We will not work with Annuity Due situations in text, however it is relatively simple to do so by making a simple adjustment to your calculator. We will include a sample example to illustrate this, however, in this textbook we will assume cash flows come at the end of each period in all of our annuity problems.

Assume you have just won a $10 Million Lottery Jackpot. However, instead of paying you the$10 Million up front, you have the choice of receiving $5 Million today or$400,000 per year at the end of each year for the next 25 years. Assuming a 6% discount rate, which would you prefer? In order to answer this, you need to find the PV of the $400,000 per year for 25 years. This is done as follows: 25 N 6 I/Y 400,000 PMT 0 FV CPT PV 5,113,342.46 (Note that we dropped the negative sign) Since the annuity is worth more than$5 Million to us, we would prefer to take the $400,000 per year for the next 25 years. # EXAMPLE THREE A – Lottery Jackpot Annuity Due (OPTIONAL) Since many lotteries actually give you your first installment TODAY if you take the installment plan, we could make the example more realistic by assuming the prize was paid as$400,000 per year at the BEGINNING of each year for the next 25 years and leave everything else the same. To adjust your calculator for this, you need to set it up to work with beginning of period payments. To do so, do the following:

2nd BGN 2nd SET ENTER

When you do this, you should see the letters “BGN” show up on the upper-right of your calculator screen to show you that your calculator is set for beginning of period payments. When you press 2nd BGN it activates the mode to change from BGN to END. Then 2nd SET toggles back and forth between BGN and END. Press the CE/C key a couple of times to clear it and you are ready to go.
Now repeat the calculation from the Example Three

25 N
6 I/Y
400,000 PMT
0 FV
CPT PV 5,420,143.01 (Note that we dropped the negative sign)

So, with beginning of period payments the jackpot is worth more to us (since we start receiving our money earlier). Now, set your calculator back to end of period payments so that you don’t end up with the wrong answer on all your other problems. To set it back, just toggle the BEG/END mode again as follows:

2nd BGN 2nd SET ENTER

You are offered an investment that pays you $1000 per year for the next 30 years. Assuming a 10% discount rate, what is this investment worth to you today? # EXAMPLE FOUR – I want to be a Millionaire You want to become a millionaire and plan to do so through a savings/investment plan. Assuming you want to reach your goal in 20 years and anticipate earning a 10% rate of return, how much must you save at the end of each year in order to reach your goal? 20 N 10 I/Y 0 PV 1,000,000 FV CPT PMT$17,459.62

This means you will need to save $17,459.62 per year in order to achieve your goal. ### PRACTICE PROBLEM FOUR Since saving$17,459.62 per year is not realistic for most of us, let’s try some adjustments. Calculate how much you would need to save under the following conditions

1. 30 years at 10%
2. 40 years at 10%
3. 30 years at 7.5%
4. 30 years at 5%

Note the large difference that time and rate of return make on savings. Having a short savings horizon or earning a low rate of return mean you must save considerably more each year to reach the same goal. This is especially important for retirement planning.

# EXAMPLE FIVE – Changing Periods per Year

Now assume that you want to accumulate $1 million in 30 years, but instead of saving each year, you are going to save every two weeks (we will earn a 10% annual rate of return). There are 26 2-week periods in each year, so now you have to adjust your calculator to work with 26 periods per year. You can do this as follows: 2nd P/Y 26 ENTER Now your calculator will recognize that you are not making annual contributions to your savings plan, but instead making a contribution every other week. Another issue when you change the number of periods per year is to recognize that the N key stands for periods and not necessarily years. Since all of our previous examples were done using 1 P/Y, the number of periods and years were the same. However, now 1 year will have 26 periods. Therefore, 30 years is equivalent to 780 periods (calculated by taking 26 times 30). Now that our adjustments have been made, we are ready to enter the problem into our calculator. 780 N 10 I/Y 0 PV 1,000,000 FV CPT PMT$202.75

If we save $202.75 every two weeks for the next 30 years and earn a 10% rate of return, we will have$1,000,000 at the end of the 30th year.

### PRACTICE PROBLEM FIVE

Repeat the above example, but now assume weekly payments (52 weeks per year) instead of payments every two weeks. Once you are done, figure out how much you are saving per year under both the once per week and once every other week alternatives and compare this to the answer we got in Practice Problem Four-1. Why are the answers different? (NOTE – Remember to reset your calculator to 1 period per year after you finish this problem).

# EXAMPLE SIX – Solving for Interest Rates

Let’s keep working with the goal of becoming a millionaire. However, instead of calculating how much you must save, we’ll assume you can save $3000 per year and want to find the rate of return you will need to earn to reach your goal. This time we will give ourselves 35 years of saving$3000 per year.

35 N
0 PV
-3000 PMT
1,000,000 FV
CPT I/Y     10.89%

# EXAMPLE SEVEN – Combining PMT, FV, and PV

Here is one last variation on our millionaire example. This time, instead of starting with nothing, let’s assume that we already have $40,000 and plan to save an additional$3000 per year over the next 35 years. Now, what rate of return must we earn in order to accumulate $1,000,000 at the end of the 35th year? 35 N -40,000 PV -3000 PMT 1,000,000 FV CPT I/Y 7.63% Note that here, we must make both the Present Value and the Annuity Payment negative as they both are flowing away from us into the savings plan. The Future Value will flow back to us at the end of the time period so it is positive. ### PRACTICE PROBLEM SEVEN You want to retire a millionaire and have accumulated$20,000 which you are putting into your retirement plan. In addition, you plan to earn a 9% rate of return. How much must you save PER MONTH over the next 35 years in order to reach your goal?

Video: Introduction and 5-Key Approach (TI-BAII+)

# EXAMPLE EIGHT – Uneven Cash Flow Stream – Present Value

Assuming a 6.5% discount rate, solve for the present value of the following cash flow stream.

Here we can no longer use the 5-key approach (technically, we CAN…it would just be a lot more tedious). Instead we want to move to the cash flow worksheet on our financial calculator. The cash flow worksheet for the TI-BAII+ follows a basic 4-step process:

1. Clear out any previous values in your cash flow worksheet
2. Enter the cash flows and frequencies in your cash flow worksheet starting with year 0
3. Enter the discount rate
4. Solve for present value

Let’s walk through this process with keystrokes using the example above:

1. CF 2nd CLR Work (this enters the cash flow worksheet module and then clears out the previous values from the worksheet)
2. 0 ENTER ↓ (this enters the CF0 which in this example is 0. Note that it will not always be zero and could have either a positive or negative value)
3. 400 ENTER ↓ (this enters the first cash flow sequence )
4. 5 ENTER ↓ (this enters the first cash flow frequency. Notice that before you pressed the 5 ENTER ↓, the onscreen display showed F1 = 1 to indicate that the default frequency is 1.)
5. 600 ENTER ↓ (this enters the second cash flow sequence)
6. 4 ENTER ↓ (this enters the second cash flow frequency)
7. 1000 ENTER ↓↓ (this enters the third cash flow sequence and accepts the default frequency of 1. Note the second down arrow which just moves us past the third frequency and sets us up for the next cash flow sequence)
8. 1300 ENTER ↓ (this enters the fourth cash flow sequence)
9. 6 ENTER (this enters the fourth – and final – cash flow frequency. Note that there is no down arrow after this as there are no more cash flows to enter. Don’t worry if you hit a down arrow…it doesn’t hurt anything, but is just not necessary)
10. NPV 6.5 ENTER ↓ (pressing the NPV button gets the calculator to ask for the discount rate. The onscreen display should say I = . This is where you put in the discount rate of 6.5% and then ENTER ↓ to move to the next – and final – step)
11. CPT (this calculates the answer. While the onscreen display will say NPV = before you press the CPT button, you won’t have the correct answer until you press CPT to actually perform the calculation. Your final answer here should be $7,047.87.) Note that the sum of your frequencies should add up to the length of the timeline (5+4+1+6 = 16). If not, you miscounted somewhere along the way. # EXAMPLE NINE – Uneven Cash Flow Stream – Future Value We can use a similar process to solve for the future value of an uneven cash flow stream. However, we will start by doing the exact same steps we did to get the present value. The reason is that to get the future value of an uneven cash flow stream we first (A) solve for the present value of the cash flow stream and then (B) figure out what that value will grow to over the time horizon. So, if the problem would have given you the same cash flow stream as above, but instead asked what it would be worth as of year 16 (the end of the time horizon). As we found above, the present value of the cash flow stream (what is worth today) is$7047.87. So, if we want to know what the cash flow stream is worth in year 16, we just bring the present value ($7047.87) forward 16 years at the 6.5% rate of return using the 5 key approach as follows: 16 N 6.5 I/Y 7047.87 PV 0 PMT CPT FV -19,304.19 This tells us that the value of the cash flows will grow to$19,304.19 at the end of the 16 year time horizon if we can invest them to earn a 6.5% rate of return. Note that the PV of an uneven cash flow stream will always be less than the sum of all the individual cash flows ($13,200 in this example) and the FV of an uneven cash flow stream will always be more than the sum of all the individual cash flows. # EXAMPLE TEN – Uneven Cash Flow Stream – Rate of Return Assume you could buy the cash flow stream in this example for$6000 today. Based on this, what would your rate of return be? To do this, we will use the IRR function on the calculator with the cash flow worksheet. This is similar to what we did above for NPV with two major changes. First, our CF0 is now the initial investment (-6000) and is negative because it is a cash flow. Second, instead of initiating the solve process by pressing the NPV and putting in the discount rate, we press the IRR and then CPT to get the discount rate. So, it looks like this:

1. CF 2nd CLR Work
2. -6000 ENTER ↓
3. 400 ENTER ↓
4. 5 ENTER ↓
5. 600 ENTER ↓
6. 4 ENTER ↓
7. 1000 ENTER ↓↓
8. 1300 ENTER ↓
9. 6 ENTER
10. IRR CPT (this calculates the answer. While the onscreen display will say IRR = before you press the CPT button, you won’t have the correct answer until you press CPT to actually perform the calculation…it may take a couple seconds. Your final answer here should be 8.39%.)

One of the most common mistakes we see on this type of problem is people putting the CF0 in as a positive value which will result in an error (no solution). The 8.39% represents the average annualized rate of return we earn over the 16 year time horizon on our $6000 investment. ### PRACTICE PROBLEMS EIGHT, NINE AND TEN Assuming a 12.5% discount rate, solve for the present value and future value of the following time line. Also, assuming you could buy the cash flow stream for$80,000, what would your rate of return be?

Video: Uneven Cash Flow Streams (TI-BAII+)

# EXAMPLE ELEVEN – Effective Annual Rate

You are offered the choice of 7.8% compounded quarterly or 7.6% compounded daily. Which is a better investment (assuming both have the same risk)? In order to address whether we are better with the higher interest rate compounded less frequently or the lower interest rate compounded more frequently, we need to make them stable comparison by converting both to their annual compounding equivalent. We do this with the effective annual rate. It can be done with a formula or your financial calculator. If we use the formula, it looks like this:

$k_{eff}=\Big(1+\frac{k_{nom}}{m}\Big)^m-1$

where

keff represents the annual equivalent
knom represents the nominal or stated interest rate
m represents the number of compounding periods per year

Plugging in our values for the 7.8% compounded quarterly we would get:

$k_{eff}=\Big(1+\frac{0.078}{4}\Big)^4-1$
$k_{eff}=(1.0195)^4-1$
$k_{eff}=1.0803-1$
$k_{eff}=0.0803$
$k_{eff}=8.03\%$

And for the 7.6% compounded daily we would get:

$k_{eff}=\Big(1+\frac{0.076}{365}\Big)^{365}-1$
$k_{eff}=(1.000208219)^{365}-1$
$k_{eff}=1.0790-1$
$k_{eff}=0.0790$
$k_{eff}=7.90\%$

In this case, the 7.8% compounded quarterly is better. If using the formulas, be sure to (A) carry out your calculations to several decimal places (or better yet, don’t round at all until you are done), (B) plug in rates into the formula as decimals, and (C) round your final answer to 2 decimal places in percentage terms. You can also do this with the financial calculator as follows:

2nd I Conv (this activates the interest conversion module – note it is the shift of the 2 key)

7.8 ENTER ↓↓ (when you enter the interest conversion module, your onscreen display should read NOM = . This is asking for the nominal interest rate which you enter as the 7.8. Once that is entered, you need to scroll down twice to get to the compounding periods per year screen.)

4 ENTER ↑ (the 4 is the compounding periods per year for quarterly. Once you enter that, you need to scroll up one to get to the effective annual rate screen)

CPT (once you are on the effective annual rate screen, just press CPT to get your final answer of 8.03%.)

For the 7.6% compounded daily it is:

2nd I Conv
7.6 ENTER ↓↓
365 ENTER ↑
CPT

This will give you your answer of 7.90% indicating that it is better to take 7.8% compounded quarterly than 7.6% compounded daily.

### PRACTICE PROBLEM ELEVEN

You are offered investments of 12% compounded annually, 11.75% compounded quarterly, or 11.5% compounded weekly. Assuming the same risk, which would you prefer?

Video: Effective Annual Rates (TI-BAII+)

45 N
9.5 I/Y
400 PV
0 PMT

30 N
10 I/Y
1000 PMT
0 FV

40 N
10 I/Y
0 PV
1,000,000 FV

30 N
5 I/Y
0 PV
1,000,000 FV
CPT PMT      $15,051.44 ## Practice Problem 5 Set Calculator to 52 Periods Per Year ⇒ 2nd P/Y 52 ENTER Calculate Number of Periods ⇒ 52 x 30 = 1560 1560 N 10 I/Y 0 PV 1,000,000 FV CPT PMT$101.07

*Remember to set your calculator back to 1 period per year when you finish the calculation.

Annual Savings Required to Accumulate $1,000,000 in 30 years at 10% A) Saving at the end of each year ⇒$6,079.25
B) Saving at end of every 2 weeks ⇒ $202.75 x 26 =$5,271.50
C) Saving at end of each week ⇒ $101.07 x 52 =$5,255.64

The more frequently we make contributions, the less we have to save each year. This is because of the compounding effect. When we make annual contributions, we earn no return the first year. With weekly contributions we start earning a return during the second week.

## Practice Problem 6

35 N
0 PV
-4500 PMT
1,000,000 FV
CPT I/Y      9.13%

420 N
9 I/Y
-20,000 PV
1,000,000 FV

## Practice Problem 9

Step 1: Solve for Present Value (See solution to 8) ⇒ $63,878.58 Step 2: Bring forward to end of year 13 13 N 12.5 I/Y 63,878.58 PV 0 PMT CPT FV$295,350.73

CF 2nd CLR Work
-80000 ENTER ↓
10000 ENTER ↓
3 ENTER ↓
12000 ENTER ↓
5 ENTER ↓
5000 ENTER ↓
2 ENTER ↓
8000 ENTER ↓↓
10000 ENTER ↓
2 ENTER
IRR CPT ⇒ 7.93%

## Practice Problem 11

Since the 12% compounded annual is already annual, there is no need for an effective annual rate.

The 11.75% compounded quarterly is
2nd I Conv
11.75 ENTER ↓↓
4 ENTER ↑
CPT     12.28%

The 11.5% compounded daily is
2nd I Conv
11.5 ENTER ↓↓
365 ENTER ↑
CPT       12.17%

Making the 11.75% quarterly the best deal.