Company ABC was incorporated on january 1, 2004. It has expected annual default rate of 10%. Assuming a constant quarterly default rate, what is the probability that company ABC will not have defaulted by April1, 2004 ?
a) 2.4%
b) 2.5%
c) 97.4%
d) 97.5%
If the quarterly default rate is d, then to survive for a year (90% chance), it has to survive all four quarters:
(1 – d)^4 = 0.9
1 – d = 0.9^(1/4) = 97.4%
d = 2.6%
The probability that it will not have defaulted by April 1 (survived one quarter) is 1 – d = 97.4%.