Collateral option valuation made easy

The option to switch the currency of posted collateral embedded in some credit support annexes may have a significant impact on the discounting of derivatives contracts. In this paper, Vladimir Sankovich and Qinghua Zhu develop an approximation for the value of the cheapest-to-deliver option, demonstrate how the necessary model parameters can be implied from historical data and show how it can be applied to baskets with any number of collateral currencies

It is by now well known that the terms of collateral posting between counterparties influence prices of derivatives contracts. These terms are typically documented in Credit SupportAnnexes(CSAs). Some CSAs allow the posting party to choose a currency (from a pre-agreed-upon set) in which collateral will be delivered.We refer to this optionality as the cheapest-to-deliver (CTD) funding option. The presence of this option may significantly alter the profile of the appropriate funding curve and