Modified duration: Difference between revisions

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imported>Doug Williamson
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(MD).  
(MD).  
Modified duration is an estimate of the market price sensitivity of an instrument, to small changes in yield.  It is the 'proportional price change' of a market instrument or portfolio.   
 
Modified duration is an estimate of the market price sensitivity of an instrument, to small changes in yield.   
 
It is the 'proportional price change' of a market instrument or portfolio.   
 


The estimate of change in market price is given by:
The estimate of change in market price is given by:


'''-Modified duration x Starting Market price x Change in yield'''
'''Modified duration x Starting Market price x Change in yield'''
 


Often - but not always - the relevant yield is defined as the annual effective yield ('EAR').
Often - but not always - the relevant yield is defined as the annual effective yield ('EAR').
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For changes in EAR, modified duration is calculated from Macaulay’s duration as:
For changes in EAR, modified duration is calculated from Macaulay’s duration as:


MD = Duration/[1+EAR].
 
MD = Duration/[1+EAR]
 


For changes in simple annual yields 'R', modified duration is calculated as:
For changes in simple annual yields 'R', modified duration is calculated as:


MD = Duration/[1+(R/n)]
MD = Duration/[1+(R/n)]


where n = number of compounding periods per year.
where n = number of compounding periods per year.


For example, say Duration = 5.00 years, Semiannual yield R = 6.00% (so n = 2) and so EAR = 6.09%.
For example, say Duration = 5.00 years, Semiannual yield R = 6.00% (so n = 2) and so EAR = 6.09%.


With respect to the EAR:
With respect to the EAR:
MD = 5.00/1.0609 = 4.71
MD = 5.00/1.0609 = 4.71


With respect to the Semiannual yield:
With respect to the Semiannual yield:
MD = 5.00/1.03 = 4.85
MD = 5.00/1.03 = 4.85


This shows that there would be a greater proportionate change in price for a 1% change in the Semiannual yield, than for a 1% change in the EAR.
This shows that there would be a greater proportionate change in price for a 1% change in the Semiannual yield, than for a 1% change in the EAR.


== See also ==
== See also ==

Revision as of 08:51, 22 August 2013

(MD).

Modified duration is an estimate of the market price sensitivity of an instrument, to small changes in yield.

It is the 'proportional price change' of a market instrument or portfolio.


The estimate of change in market price is given by:

Modified duration x Starting Market price x Change in yield


Often - but not always - the relevant yield is defined as the annual effective yield ('EAR').

For changes in EAR, modified duration is calculated from Macaulay’s duration as:


MD = Duration/[1+EAR]


For changes in simple annual yields 'R', modified duration is calculated as:


MD = Duration/[1+(R/n)]

where n = number of compounding periods per year.


For example, say Duration = 5.00 years, Semiannual yield R = 6.00% (so n = 2) and so EAR = 6.09%.

With respect to the EAR:

MD = 5.00/1.0609 = 4.71

With respect to the Semiannual yield:

MD = 5.00/1.03 = 4.85

This shows that there would be a greater proportionate change in price for a 1% change in the Semiannual yield, than for a 1% change in the EAR.


See also