The SABR/LIBOR Market Model (ePub)

This book presents a major innovation in the interest rate space.
It explains a financially motivated extension of the LIBOR Market
model which accurately reproduces the prices for plain vanilla
hedging instruments (swaptions and caplets) of all strikes and
maturities produced by the SABR model. The authors show how to
accurately recover the whole of the SABR smile surface using their
extension of the LIBOR market model. This is not just a new model,
this is a new way of option pricing that takes into account the
need to calibrate as accurately as possible to the plain vanilla
reference hedging instruments and the need to obtain prices and
hedges in reasonable time whilst reproducing a realistic future
evolution of the smile surface. It removes the hard choice between
accuracy and time because the framework that the authors provide
reproduces today's market prices of plain vanilla options almost
exactly and simultaneously gives a reasonable future evolution for
the smile surface.

The authors take the SABR model as the starting point for their
extension of the LMM because it is a good model for European
options. The problem, however with SABR is that it treats each
European option in isolation and the processes for the various
underlyings (forward and swap rates) do not talk to each other so
it isn't obvious how to relate these processes into the dynamics of
the whole yield curve. With this new model, the authors bring the
dynamics of the various forward rates and stochastic volatilities
under a single umbrella. To ensure the absence of arbitrage they
derive drift adjustments to be applied to both the forward rates
and their volatilities. When this is completed, complex derivatives
that depend on the joint realisation of all relevant forward rates
can now be priced.

Contents

THE THEORETICAL SET-UP

The Libor Market model

The SABR Model

The LMM-SABR Model

IMPLEMENTATION AND CALIBRATION

Calibrating the LMM-SABR model to Market Caplet prices

Calibrating the LMM/SABR model to Market Swaption Prices

Calibrating the Correlation Structure

EMPIRICAL EVIDENCE

The Empirical problem

Estimating the volatility of the forward rates

Estimating the correlation structure

Estimating the volatility of the volatility

HEDGING

Hedging the Volatility Structure

Hedging the Correlation Structure

Hedging in conditions of market stress