The Time Value of Money Laurence Booth Sean Cleary and Pamela Peterson Drake Outline of the chapter 51 Time value of money Simple interest Simple interest is interest that is paid only on the principal amount ID: 437019
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Slide1
Chapter 5The Time Value of Money
Laurence Booth, Sean Cleary and Pamela Peterson DrakeSlide2
Outline of the chapterSlide3
5.1 Time value of moneySlide4
Simple interest
Simple interest
is interest that is paid only on the principal amount.
Interest = rate × principal amount of loanSlide5
Simple interest: example
A
2-year loan of $1,000 at 6% simple interest
At the end of the first year,
interest = 6% × $1,000 = $60
At the end of the second year,
interest = 6% × $1,000 = $60
and loan
repayment of $1,000Slide6
Compound interest
Compound interest
is interest paid on both the principal and any accumulated interest.
Interest =
Slide7
Compounding
Compounding
is translating a present value into a future value, using compound interest.
Future value interest factor
is also referred to as the
compound factor
.
Slide8
Terminology and notation
Term
Notation
Meaning
Future value
FV
Value at some specified future point in time
Present value
PV
Value today
Interest
i
Compensation for the use of funds
Number of periods
nNumber of periods between the present value and the future valueCompound factor(1 + i)
n
Translates a present value into a future valueSlide9
Compare: simple versus compound
Suppose you deposit $5,000 in an account that pays 5% interest per year. What is the balance in the account at the end of four years if interest is:
Simple interest?
Compound interest?Slide10
Simple interest
Year
Beginning
Add interest
Ending
1
$5,000.00
+ (5% × $5,000) =
$5,250.00
2
$5,250.00
+ (5% × $5,000) =
$5,500.00
3
$5,500.00
+ (5% × $5,000) =
$5,750.00
4
$5,750.00
+ (5% × $5,000) =
$6,000.00Slide11
Compound interest
Year
Beginning
Compounding
Ending
1
$5,000.00
× 1.05 =
$5,250.00
2
$5,250.00
× 1.05 =
$5,512.50
3
$5,512.50
× 1.05 =
$5,788.13
4
$5,788.13
× 1.05 =
$6,077.53Slide12
Interest on interest
How much interest on interest?
Interest on interest =
FV
compound
–
FV
simple
Interest on interest = $6,077.53 – 6,000.00 =
$77.53Slide13
Comparison
Year
End
of year balance
Simple interest
Compound interest
0
$5,000.00
$5,000.00
1
$5,250.00
$5,250.00
2
$5,500.00
$5,512.50
3
$5,750.00
$5,788.13
4
$6,000.00
$6,077.53Slide14
Try it: Simple v. compound
Suppose you are comparing two accounts:
The Bank A account pays 5.5% simple interest.
The Bank B account pays 5.4% compound interest.
If you were to deposit $10,000 in each, what balance would you have in each bank at the end of five years?Slide15
Try it: Answer
Bank A: $12,750.00
Bank B: $13,007.78Slide16
A note about interest
Because compound interest is so common, assume that interest is compounded unless otherwise indicated.Slide17
Short-cuts
Example:
Consider
$
1,000
deposited for
three years
at
6%
per year
.Slide18
The long way
FV
1
= $1,000.00 × (1.06) = $1,060.00
FV
2
=
$
1,060.00 ×
(
1.06)
= $1,123.60FV3 = $1,123.60 × (1.06) = $1,191.02orFV3
= $1,000 × (1.06)
3
= $1,191.02 orFV3 = $1,000 × 1.191016 = $1,191.02
Future value factorSlide19
Short-cut: Calculator
Known values:
PV = 1,000
n = 3
i = 6%
Solve for:
FVSlide20
Input three known values, solve for the one unknown
HP10B
BAIIPlus
HP12C
TI83/84
1000 +/- PV
3 N
6 I/
YR
FV
1000 +/- PV
3 N
6 I/
YR
FV
1000 CHS PV
3 n
6
i
FV
[APPS] [Finance]
[
TVM
Solver]
N =3
I%=6
PV = -1000
FV [Alpha] [Solve}Known: PV, i , nUnknown: FVSlide21
Short-cut: spreadsheetMicrosoft Excel or Google Docs
=
FV
(
RATE,NPER,PMT,PV,TYPE
)
TYPE default is 0, end of period
=
FV
(.06,3,0,-1000)
or
A
1
6%
2
3
3
-1000
4
=
FV
(A1,A2,0,A3)Slide22
Problems Set 1Slide23
Suppose you deposit $2,000 in an account that pays 3.5% interest annually.
How much will be in the account at the end of three years?
How much of the account balance is interest on interest?
Problem 1.1
23Slide24
If you invest $100 today in an account that pays 7% each year for four years and 3% each year for five years, how much will you have in the account at the end of the nine years?
Problem 1.2
24Slide25
DiscountingSlide26
Discounting
Discounting
is translating a future value into a present value.
The
discount factor
is the inverse of the compound factor:
To translate a future value into a present value, PV=
Slide27
Example
Suppose you have a goal of saving $100,000 three years from today. If your funds earn 4% per year, what lump-sum would you have to deposit today to meet your goal?Slide28
Example, continued
Known values:
FV
= $100,000
n = 3
i = 4%
Unknown: PVSlide29
Example, continued
PV =
=
PV = $100,000 × 0.8889964
PV = $88,899.64
Check:
FV
3
= $88,899.64 × (1 + 0.04)
3
= $100,000
Slide30
Short-cut: Calculator
HP10B
BAIIPlus
HP12C
TI83/84
100000 +/- PV
3 N
4 I/
YR
PV
100000
+/- PV
3 N
4 I/
YR
PV
100000 CHS PV
3n
4i
PV
[APPS] [Finance] [
TVM
Solver]
N =3
I%=4
FV
= 100000
PV [Alpha] [Solve]Slide31
Short-cut: spreadsheetMicrosoft Excel or Google Docs
=PV(
RATE,NPER,PMT,PV,TYPE
)
TYPE default: end of period
=PV(.06,3,0,-1000)
or
A
1
6%
2
3
3
100000
4
=PV(A1,A2,0,A3)Slide32
Try it: Present value
What is the today’s value of $10,000 promised ten years from now if the discount rate is 3.5%?Slide33
Try it: Answer
Given:
FV
= $10,000
N = 10
I = 3.5%
Solve for PV
PV =
= $7,089.19
Slide34
Frequency of compounding
If interest is compounded more than once per year, we need to make an adjustment in our calculation.
The
stated rate
or nominal rate of interest is the
annual percentage rate
(
APR
).
The rate per period depends on the frequency of compounding.Slide35
Discrete compounding:Adjustments
Adjust the number of periods and the rate per period.
Suppose the nominal rate is 10% and compounding is quarterly:
The rate per period is 10%
4 = 2.5%
The number of periods is
number of years × 4Slide36
Continuous compounding:Adjustments
The compound factor is
e
APR
x n
.
The discount factor is
.
Suppose the nominal rate is 10%.
For five years, the continuous compounding factor is e
0.10 x 5
= 1.6487
The continuous compounding discount factor for five years is 1 ÷
e
0.10 x 5 = 0.60653 Slide37
Try it: Frequency of compounding
If you invest $1,000 in an investment that pays a nominal 5% per year, with interest compounded semi-annually, how much will you have at the end of 5 years?Slide38
Try it: Answer
Given:
PV = $1,000
n = 5 × 2 = 10
i = 0.05
2 =
0.25
Solve for
FV
FV
= $1,000
× (1 + 0.025)10 = $1,280.08Slide39
Problem Set 2Slide40
Suppose you set aside an amount today in an account that pays 5% interest per year, for five years. If your goal is to have $1,000 at the end of five years, what would you need to set aside today?
Problem 2.1
40Slide41
Suppose you set aside an amount today in an account that pays 5% interest per year, compounded quarterly, for five years. If your goal is to have $1,000 at the end of five years, what would you need to set aside today?
Problem 2.2
41Slide42
Suppose you set aside an amount today in an account that pays 5% interest per year, compounded continuously, for five years. If your goal is to have $1,000 at the end of five years, what would you need to set aside today?
Problem 2.3
42Slide43
5.2 Annuities and Perpetuities
0
1
2
3
4
5
|
|
|
|
|
|
CF
CF
CF
CF
CF
PV?
FV
?Slide44
What is an annuity?
An
annuity
is a periodic cash flow.
Same amount each period
Regular intervals of time
The different types depend on the timing of the first cash flow.Slide45
Type of annuities
Type
First cash flow
Examples
Ordinary
One period
from today
Mortgage
Annuity due
Immediately
Lottery payments
Rent
Deferred annuity
Beyond one period from today
Retirement savingsSlide46
Time lines: 4-payment annuity
0
1
2
3
4
5
|
|
|
|
|
|
Ordinary
PV
CF
CF
CF
CF
FV
Annuity due
CF
PV
CF
CF
CF
FV
Deferred annuity
PV
CF
CF
CF
CF
FVSlide47
Key to valuing annuities
The key to valuing annuities is to get the timing of the cash flows correct.
When in doubt, draw a time line.Slide48
Example: PV of an annuity
What is the present value of a series of three cash flows of $4,000 each if the discount rate is 6%, with the first cash flow one year from today?
0
1
2
3
4
|
|
|
|
$4,000
$4,000
$4,000Slide49
Example: PV of an annuityThe long way
0
1
2
3
4
|
|
|
|
$4,000
$4,000
$4,000
$3,773.58
3,559.99
3,358.48
$10,692.05Slide50
Example: PV of an annuityIn table form
Year
Cash flow
Discount factor
Present value
1
$4,000.00
0.94340
$3,773.58
2
$4,000.00
0.89000
3,559.99
3
$4,000.00
0.83962
3,358.48
2.67301
$10,692.05
PV = $4,000.00 × 2.67301 = $10,692.05 Slide51
Example: PV of an annuityFormula short-cuts
PV =
PV = $4,000 × 2.67301
PV = $10,692.05
Slide52
Example: PV of an annuityCalculator short cuts
Given:
PMT
= $4,000
i = 6%
N = 3
Solve for PVSlide53
Example: PV of an annuitySpreadsheet short-cuts
=
PV(
RATE,NPER,PMT,FV,TYPE
)
=PV(.06,3,4000,0)
Note: Type is important for annuities
If Type is left out, it is assumed a 0
0 is for an ordinary annuity
1 is for an annuity dueSlide54
Example: FV of an annuity
What is the future value of a series of three cash flows of $4,000 each if the discount rate is 6%, with the first cash flow one year from today?
0
1
2
3
4
|
|
|
|
$4,000
$4,000
$4,000Slide55
Example: FV of an annuity
The long way
0
1
2
3
4
|
|
|
|
$4,000.00
$4,000.00
$4,000.00
4,240.00
4,494.40
$12,734.40Slide56
Example: FV of an annuity
In table form
Year
Cash flow
Compound factor
Future value
1
$4,000.00
1.1236
$4,494.40
2
$4,000.00
1.0600
4,240.00
3
$4,000.00
1.0000
4,000.00
3.1836
$12,734.40
PV = $4,000.00 × 3.1836 = $12,734.40 Slide57
Example: FV of an annuity
Calculator short cuts
CALCULATOR
Given:
PMT
= $4,000
i = 6%
N = 3
Solve for
FVSlide58
Example: FV of an annuity
Spreadsheet short-cuts
=
FV
(
RATE,NPER,PMT,PV,type
)
=
FV
(.06,3,4000,0)Slide59
Annuity due
Consider a
series of three cash flows of $4,000 each if the discount rate is 6%, with the first cash flow
today.
What is the present value of this annuity?
What is the future value of this annuity?Slide60
The time line
0
1
2
3
|
|
|
|
$4,000.00
$4,000.00
$4,000.00
PV?
FV
?
This is an annuity dueSlide61
Valuing an annuity due
Present value
Year
End of year cash flow
Compound factor
Present value of cash flow
0
$4,000.00
1.00000
$4,000.00
1
$4,000.00
0.94340
3,773.58
2
$4,000.00
0.89000
3,559.99
2.83339
$11,333.57
Future value
Year
End of year cash flow
Factor
Future value
0
$4,000.00
1.19102
$4,764.06
1
$4,000.00
1.12360
4,494.40
2
$4,000.00
1.06000
4,240.00
3.37462
$13,498.46Slide62
Valuing an annuity due: Using calculators
Present value
PMT
= 4000
N = 3
I = 6%
BEG mode
Solve for PV
Future value
PMT
= 4000
N = 3
I = 6%
BEG mode
Solve for
FVSlide63
Valuing an annuity due: Using spreadsheets
Present value
=PV(
RATE,NPER,PMT,FV,TYPE
)
=PV(0.06,3,4000,0,1)
Future value
=PV(
RATE,NPER,PMT,FV,TYPE
)
=PV(0.06,3,4000,0,1
)Slide64
Any other way?
There is one period difference between an ordinary annuity and an annuity due. Therefore:
PV
annuity
due
=
PV
ordinary
annuity
× (1 + i)
and
FVannuity due = FVordinary annuity × (1 + i)Slide65
Valuing a deferred annuity
A
deferred annuity
is an annuity that begins beyond one year from today.
That means that it could begin 2, 3, 4, … years from today, so each problem is unique.Slide66
Valuing a deferred annuity
0
1
2
3
4
5
|
|
|
|
CF
CF
CF
CF
4-payment ordinary annuity, then discount value one period
PV
0
←PV
1
4-payment annuity due, then discount value two periods
PV
0
←PV
2Slide67
Example: Deferred annuity
What is the value today of a series of five cash flows of $6,000 each, with the first cash flow received four years from today, if the discount rate is 8%?
0
1
2
3
4
5
6
7
8
9
10
|
|
|
|
|
PV?
CF
CF
CF
CF
CFSlide68
Example, cont.
Using an ordinary annuity:
PV
3
= $23,956.26
PV
0
= $19,017.25
Using an annuity due:
PV
4
= $25,872.76PV0 = $19,017.25Discount 3 periods at 8%
Discount 4 periods at 8%Slide69
Example: Deferred annuityCalculator solutions
HP10B
BAIIPlus
TI83/84
0 CF
0 CF
0 CF
0 CF
6000 CF
6000 CF
6000 CF
6000 CF6000 CF8 i
NPV
0 CF ↑ 1
0 CF ↑ 1 F10 CF ↑ 1 F20 CF ↑ 1 F36000 CF ↑ 1 F4
6000 CF ↑ 1 F5
6000 CF ↑ 1 F6
6000 CF ↑ 1 F7
6000 CF ↑ 1 F8
8 i
NPV
[2
nd
] {
0 0 0 6000 6000 6000 6000 6000}
STO
[2
nd] L1[APPS] [Finance][ENTER] 7NPV(.08,0,L1)[ENTER]Slide70
Example: Deferred annuitySpreadsheet solutions
A
B
Year
Cash flow
1
1
$0
2
2
$0
3
3
$0
4
4
$6000
5
5
$6000
6
6
$6000
7
7
$6000
8
8
$6000
=PV(0.08,3,0,PV(0.08,5,6000,0))
=PV(0.08,4,0,PV(0.08,5,6000,0,1))
=
NPV
(0.08,A1:A9)Slide71
Perpetuities
A
perpetuity
is an even cash flows that occurs at regular intervals of time, forever.
The valuation of a perpetuity is simple:
+
+
+…
Slide72
Problem Set 3Slide73
Which do you prefer if the appropriate discount rate is 6% per year:
An annuity of $4,000 for four annual payments starting today.
An annuity of $4,100 for four annual payments, starting one year from today.
An annuity of $4,200 for four annual payments, starting two years from today.
Problem 3.1
73Slide74
5.3 Nominal and effective rates
%
iSlide75
APR & EAR
The
annual percentage rate
(
APR
) is the nominal or stated annual rate.
The APR ignores compounding within a year.
The APR understates the true, effective rate.
The
effective annual rate
(
EAR) incorporates the effect of compounding within a year.Slide76
APR EAR
EAR =
Suppose interest is stated as 10% per years, compounded quarterly.
EAR
=
EAR = 10.3813%
Slide77
EAR with continuous compounding
77
EAR =
Suppose interest is stated as 10% per years, compounded continuously.
EAR
=
EAR = 10.5171%
Slide78
Frequency of compounding
If interest is compounded more frequently than annually, then this is considered in compounding and discounting.
There are two approaches
Adjust the i and n; or
Calculate the EAR and use thisSlide79
Example: EAR & compounding
Suppose you invest $2,000 in an investment that pays 5% per year, compounded quarterly. How much will you have at the end of 4 years?Slide80
Example: EAR & compounding
Method 1:
FV
= $2,000 (1 + 0.0125)
16
= $2,439.78
Method 2:
EAR = (1 +
)
4
– 1 = 5.0945%
FV = $2,000 (1 + 0.050945)4
= $2,439.78
Slide81
Try it: APR & EAR
Suppose a loan has a stated rate of 9%, with interest compounded monthly. What is the effective annual rate of interest on this loan?Slide82
Try it: Answer
EAR
=
EAR
EAR =
9.3807%
Slide83
Problem Set 4Slide84
What is the effective interest rate that corresponds to a 6% APR when interest is compounded monthly?
Problem 4.1
84Slide85
What is the effective interest rate that corresponds to a 6% APR when interest is compounded continuously?
Problem 4.2
85Slide86
5.4 ApplicationsSlide87
Saving for retirement
Suppose you estimate that you will need $60,000 per year in retirement. You plan to make your first retirement withdrawal in 40 years, and figure that you will need 30 years of cash flow in retirement. You plan to deposit funds for your retirement starting next year, depositing until the year before retirement. You estimate that you will earn 3% on your funds.
How much do you need to deposit each year to satisfy your plans?Slide88
Deferred annuity time line
0
1
2
3
4
5
6
7
8
…
39
40
41
42
43
…
79
|
|
|
|
|
|
|
|
|
||||
|
D
D
D
D
D
D
D
D
W
W
W
W
W
W
D = Deposit (39 in total)
W = Withdrawal (30 in total)Slide89
Deferred annuity time line
0
1
2
3
4
5
6
7
8
…
39
40
41
42
43
…
79
|
|
|
|
|
|
|
|
|
||||
|
W
W
W
W
W
PV
← Ordinary annuity
↓
Ordinary
annuity
→
FV
D
D
D
D
D
D
D
D
…
DSlide90
Two steps
Step 1: Present value of ordinary annuity
N = 30; i = 3%;
PMT
= $60,000
PV
39
= $1,176,026.48
Step 2: Solve for payment in an ordinary annuity
N = 39; i = 3%;
FV
= $1,176,026.48PMT = $16,280.74Slide91
What does this mean?
If there are 39 annual deposits of $16,280.74 each and the account earns 3%, there will be enough to allow for 30 withdrawals of $60,000 each, starting 40 years from today.Slide92
Balance in retirement accountSlide93
Practice problems
$
€
=
¥
+
£Slide94
Problem 1
What is the future value of $2,000 invested for five years at 7% per year, with interest compounded annually?Slide95
Problem 2
What is the value today of €10,000 promised in four years if the discount rate is 4%?Slide96
Problem 3
What is the present value of a series of five end-of-year cash flows of $1,000 each if the discount rate is 4%?Slide97
Problem 4
Suppose you plan to save $3,000 each year for ten years. If you earn 5% annual interest on your savings, how much more will you have at the end of ten years if you make your payments at the beginning of the year instead of the end of the year?Slide98
Problem 5
Sue plans to deposit $5,000 in a savings account each year for thirty years, starting ten years from today. Yan plans to deposit $3,500 in a savings account each year for forty years, starting at the end of this year. If both Sue and Yan earn 3% on their savings, who will have the most saved at the end of forty years?Slide99
Problem 6
Suppose you have two investment opportunities:
Opportunity 1: APR of 12%, compounded monthly
Opportunity 2: APR of 11.9%, compounded continuously
Which opportunity provides the better return?Slide100
Problem 7
If you can earn 5% per year, what would you have to deposit in an account today so that you have enough saved to allow withdrawals of $40,000 each year for twenty years, beginning thirty years from today?Slide101
Problem 8
Suppose you deposit ¥50000 in an account that pays 4% interest, compounded continuously. How much will you have in the account at the end of ten years if you make no withdrawals?Slide102
The end