psaspeed2rate

Single monthly mortality rate given PSA speed

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Syntax

[CPRPSA,SMMPSA] = psaspeed2rate(PSASpeed)

Description

[CPRPSA,SMMPSA] = psaspeed2rate(PSASpeed) calculates vectors of PSA prepayments, each containing 360 prepayment elements, to represent the 360 months in a 30-year mortgage pool.

example

Examples

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Open Live Script

This example shows how to compute the prepayment and mortality rates, given a mortgage-backed security with annual speed set at the PSA default benchmark. 

PSASpeed = [100 200];
 
[CPRPSA, SMMPSA]= psaspeed2rate(PSASpeed)
CPRPSA = 360×2

    0.0020    0.0040
    0.0040    0.0080
    0.0060    0.0120
    0.0080    0.0160
    0.0100    0.0200
    0.0120    0.0240
    0.0140    0.0280
    0.0160    0.0320
    0.0180    0.0360
    0.0200    0.0400
    0.0220    0.0440
    0.0240    0.0480
    0.0260    0.0520
    0.0280    0.0560
    0.0300    0.0600
      ⋮


SMMPSA = 360×2

    0.0002    0.0003
    0.0003    0.0007
    0.0005    0.0010
    0.0007    0.0013
    0.0008    0.0017
    0.0010    0.0020
    0.0012    0.0024
    0.0013    0.0027
    0.0015    0.0031
    0.0017    0.0034
    0.0019    0.0037
    0.0020    0.0041
    0.0022    0.0044
    0.0024    0.0048
    0.0025    0.0051
      ⋮


% view the plot of the output
psaspeed2rate(PSASpeed)

Figure contains an axes object. The axes object contains 2 objects of type line.

Input Arguments

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Annual speed relative to the benchmark, specified as any value > 0 using an NSPD-by-1 vector. The PSA benchmark is 100.

Data Types: double

Output Arguments

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PSA conditional prepayment rate, returned as a 360-by-NSPD vector in decimals.

PSA monthly default rate, returned as a 360-by-NSPD vector in decimals.

More About

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References

[1] PSA Uniform Practices, SF-49

Version History

Introduced before R2006a

See Also

Topics