Replication of flexi-swaps

Ingmar Evers and Farshid Jamshidian describe a relatively new product known as a flexi-swap and discuss its application in securitisation. A flexi-swap gives a counterparty an option to amortise the interest rate swap at an accelerated pace. They show that it can be replicated semi-statically by a vanilla amortising swap plus a portfolio of Bermudan swaptions. The derivation employs a novel ‘high-low interest rate path’ argument, which results in a simple algebraic formula for the weights