Swaption Approach

Formula:

Cva swaption

 

The swaption approach models EPE as a series of swaptions and is only applicable where the derivative is an IR swap.

Simplistically, the exposure is modelled as:

- an option on a reversed swap in case the counterparty defaults before the first CF date +

- + an option on the reversed swap excluding the first CF in case the counterparty defaults between the first and second CF dates

- etc... 

 

The number of swaptions is determined by the remaining term of the contract and the payment frequency. 

 

Terms: 

Swaptiont = fair value of an option with expiry t on a swap opposite to the derivative, with maturity T – t. 

PD(t-1, t) = probability of default between time t – 1 and t. 

The CVA calculation utilises counterparty PDs, while for DVA own PDs are used. 

 

 

Advantages:

- methodology takes both current and potential future exposure into account 

- considers bilateral nature of derivatives 

- can be applied on transactional level 

- terms of swaptions are easy to determine

- intuitive appeal as the CVA is based on the cost of replacing the asset 

 

Disadvantages:

- applies to IR swap exposures only

- difficulty to apply on counterparty level, especially when exposure to counterparty includes derivatives other than IR swap. 

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