Annuity factor: Difference between revisions

From ACT Wiki
Jump to navigationJump to search
imported>Doug Williamson
(Categorise the page and link with technical skills pages.)
imported>Doug Williamson
(Updated entry. Source ACT Glossary of terms)
Line 3: Line 3:
(AF).   
(AF).   


1.


The purpose of Annuity factors is to answer questions of the type:
A method for calculating the total present value of a simple fixed [[annuity]].  
 
"What is the value today (at Time 0) of a promise to receive $10m at Time 1 year (one year into the future) and a further $10m every year until the end of a predetermined fixed future period."
 
 
An annuity factor is a method for calculating the total present value of a simple fixed [[annuity]].
 
Such an annuity is a finite series of fixed future cash flows, the first cash flow being at Time 1 period hence, and the last one being at Time n periods hence.


Mathematically, the Annuity Factor is the cumulative [[Discount factor]] for maturities 1 to n inclusive, when the [[cost of capital]] is the same for all relevant maturities.
Mathematically, the Annuity Factor is the cumulative [[Discount factor]] for maturities 1 to n inclusive, when the [[cost of capital]] is the same for all relevant maturities.
Line 30: Line 24:




The Time 1 cash flow being the cash flow which occurs one period into the future.
'''Example'''
 
Today being Time 0.
 
 
'''''Example'''''


For example, when the Annuity factor in relation to two fixed cash flows at Time 1 and Time 2 = 1.833  
For example, when the Annuity factor = 1.833 and the Time 1 cash flow = $10m, then:
 
and the Time 1 period hence cash flow = $10m, then:


Present value = AF x Time 1 cash flow
Present value = AF x Time 1 cash flow
Line 45: Line 32:
= 1.833 x $10m
= 1.833 x $10m


= '''$18.33m'''
= $18.33m
 




Line 64: Line 50:




'''''Example'''''
'''Example'''


For example, when the periodic cost of capital (r) = 6% and the number of periods in the total time under review (n) = 2, then:
For example, when the periodic cost of capital (r) = 6% and the number of periods in the total time under review (n) = 2, then:
Line 86: Line 72:




The Annuity Factor is sometimes also known as the Annuity formula.
2.
 
Annuity factors are also used to calculate equated loan instalments.
 
For a loan drawn down in full at the start, the equated loan instalment is given by:
 
Instalment = Principal/Annuity factor
 
 
'''Example'''
$20m is borrowed at an annual interest rate of 6%.
 
The loan is to be repaid in two equal annual instalments, starting one year from now.
 
 
The annuity factor is 1.833 (as before).
 
The loan instalment is:
 
$20m/1.833
 
= $10.9m
 
 
 
The Annuity Factor is sometimes also known as the ''Annuity formula''.




Line 96: Line 107:
* [[Perpetuity factor]]
* [[Perpetuity factor]]
* [[Present value]]
* [[Present value]]
* [[Instalment]]
* [[Equated instalment]]
* [[Principal]]


[[Category:Financial_management]]
[[Category:Financial_management]]

Revision as of 11:15, 19 November 2014

Financial maths.

(AF).

1.

A method for calculating the total present value of a simple fixed annuity.

Mathematically, the Annuity Factor is the cumulative Discount factor for maturities 1 to n inclusive, when the cost of capital is the same for all relevant maturities.


Commonly abbreviated as AF(n,r) or AFn


Also known as the Present Value Interest Factor of an Annuity (PVIFA).


Present value calculation

The present value of the annuity is calculated from the Annuity Factor (AF) as:

= AF x Time 1 cash flow.


Example

For example, when the Annuity factor = 1.833 and the Time 1 cash flow = $10m, then:

Present value = AF x Time 1 cash flow

= 1.833 x $10m

= $18.33m


Annuity factor calculation

The annuity factor for 'n' periods at a periodic yield of 'r' is calculated as:

AF(n,r) = 1/r x [1-(1+r)-n]


where

n = number of periods, and

r = periodic cost of capital.


Example

For example, when the periodic cost of capital (r) = 6% and the number of periods in the total time under review (n) = 2, then:

Annuity factor = 1/r x [1-(1+r)-n]

= 1/0.06 x [1-(1 + 0.06)-2]

= 1.833


This figure is also the sum of the two related Discount Factors:

AF2 = DF1 + DF2

= 1.06-1 + 1.06-2

= 0.9434 + 0.8900

= 1.833


2.

Annuity factors are also used to calculate equated loan instalments.

For a loan drawn down in full at the start, the equated loan instalment is given by:

Instalment = Principal/Annuity factor


Example $20m is borrowed at an annual interest rate of 6%.

The loan is to be repaid in two equal annual instalments, starting one year from now.


The annuity factor is 1.833 (as before).

The loan instalment is:

$20m/1.833

= $10.9m


The Annuity Factor is sometimes also known as the Annuity formula.


See also