default swap

Dear Alll:

According to the problem below, why is it that the default correlation are lower?

Thank yoo so much for your time

Which of the following most accurately describes the pricing of a first-to-default basket of credit default swaps in a correlation trade? The swap premium will be higher when the number of credit default swaps is:

A) higher and when the default correlations are lower. B) higher and when the default correlations are higher. C) lower and when the default correlations are higher.

Your answer: A was correct!

In one type of correlation trade, the investor sells protection on a basket of credit default swaps. One such basket is a first-to-default swap, where the number of credit default swaps in the basket is typically five. In this structure, the investor would provide protection for the first (and only the first) default. If one of the reference obligations defaults, the investor owes the basket’s notional amount and receives the defaulted reference obligation. The pricing of the basket default swap depends on the default correlation, which is the probability that two of the reference obligations in a basket will default concurrently. Higher default correlations result in lower premiums (the protection offered by the first-to-default basket is worth less to the protection buyer when it is likely that several of the obligations will default at the same time). The higher the number of credit default swaps in the basket, the higher the basket’s premium (there is a greater probability of one of them defaulting).

If correlations are lower, there are more scenarios where at least one default happens. To illustrate, let’s say your basket has two securities, and default probability for each security is 50%. Let’s say condition 1 is no default and condition 0 is a default.

If correlation is 1 (highest possible correlation/perfect correlation), the scenarios are:

{0, 0} and {1, 1}, each with 50% probability. Probability of at least one default is 50%.

If correlation is 0 (completely independent), the scenarios are:

{0, 0}, {0, 1}, {1, 0}, {1, 1}, each with 25% probability. Probability of at least one default is 75%.

If correlation is -1, the scenarios are:

{1, 0} and {0, 1}. Probability of default is 100%

So as you can see from this example, if correlation is high, there are more “blank” scenarios where no default happens. If correlation decreases to zero, at least one security can fall into a default scenario even if other securities don’t default. If correlation is negative, a non-default in some securities makes a default in other securities more likely.