In the context of commercial financing of developing countries, financial engineering and liability management are techniques that aim to cushion interest rate and currency shocks to debtor countries through hedging. For instance, interest rate swaps and interest rate caps reduce the interest rate sensitivity of existing liabilities by converting floating-rate borrowings into fixed-rate liabilities or by putting a ceiling on future interest rates. Similarly currency swaps can hedge currency exposure and alter the currency mix of a debt portfolio to match the composition of the debtor's export revenues. Financial hedges of this type involve a risk for the provider of the hedge that the purchaser - in this instance the debtor country - will not fulfil his obligations when the contract matures. This restricts use of these techniques to borrowers that have remained creditworthy, unless the risk can be guaranteed by a creditworthy third party.