John and Joan Popplewell just won their state’s lottery and the prize was listed as
$5,000,000. When they purchased the winning ticket, they had a choice of taking the
prize over 20 years or taking one cash payment now. The $5,000,000 represents the sum
of 20 annual payments of $250,000 each. The series of equal payments is called an
annuity. Because they chose the single cash payment, they do not actually receive
$5,000,000 in cash. The amount that they receive is the present value of an annuity.
In Chapter 22, we discussed corporate and government bonds. When a corporation
issues $10,000,000 worth of 8%, 20-year bonds, the corporation is simply borrowing
money from the public for 20 years. Each $1,000 bond pays 8% (or $80) each year. The
$80 is paid out in two $40 payments every 6 months for 20 years. The series of $40 inter-
est payments is an annuity. The amount that someone pays for the bond is the present
value of the annuity. Some investors may worry that the corporation won’t have
$10,000,000 available in 20 years to repay the bonds. Therefore, the corporation may
decide to make 20 equal annual payments into a separate account managed by a neutral
third party. At the end of the 20 years, the deposits plus accumulated interest will be
worth the $10,000,000. This fund of deposits is called a sinking fund. Equal deposits
into a sinking fund form an annuity. The total amount is the future value of an annuity.
462 Part 6 Corporate and Special Applications
23.1 Chapter 16 must be covered be-
fore Chapter 23.
23.2 If consumers purchase on credit,
they must pay the interest.If they save
in advance for their purchases,they
will receive the interest.
An annuity is made up of a series of equal payments that occur at regular time intervals.
The payments go into—or come out of—an interest-bearing account or investment. The
constant interest rate is compounded at the same time the payments are made. (Perhaps
obviously, the number of periods in an annuity is the same as the number of payments.)
We can illustrate an annuity by drawing a straight line, called a time line. On the time
line, we insert equal marks and the payment dates, and write in the payment amounts.
EXAMPLE A
An annuity has four annual payments of $1,000, always on December 31. The date of the
first $1,000 payment is December 31, 2010. Draw a time line showing the four years—
2010, 2011, 2012, and 2013—and the four payments.
The annuity illustrated in Figure 23-1, with the payments occurring at the end of
each period, is called an ordinary annuity. In this book, every annuity will have its
payments at the end of each period. The date December 31, 2009, is the beginning of
the annuity, and the date December 31, 2013, is the end of the annuity.
1
Learning Objective
Compute the future value of an
annuity.
23.3 In a very technical course,you
would emphasize that,for the basic ta-
bles and formulas to be used,(1) the
payments must be equal;(2) the pay-
ments must be regular;(3) the interest
rate must stay the same; and (4) the
compounding must coincide with the
payments.In this book,all of these de-
tails are assumed so that students can
concentrate on the fundamental
concept.
23.4 Another common type of annuity
is the annuity due, in which the pay-
ments come at the beginning of the
periods.Change Figure 23-1 so that the
first payment is on 12/31/09 but the
time line still stops at 12/31/13.An
example of an annuity due is a lease or
rental contract;you don’t move into an
apartment or office unless you pay at
least a month’s rent in advance of the
first month.We don’t cover annuities
due because the calculations aren’t
quite as straightforward.
Figure 23-1 Diagram of an Ordinary Annuity
Date
Period
Payment
12/31/09
$0
1234
12/31/10
$1,000
12/31/11
$1,000
12/31/12
$1,000
12/31/13
$1,000
Again, the value of the annuity at the end of the annuity is called the future value of
the annuity. In example A, it is the total value of all payments plus the compound
Computing the Future Value of an Annuity