May 23rd, 2003, 8:49 am
Hi,Make a search on technical forum and you will find many threads on that topic.I would say 3f-HJM /3f-BGM are market practises, even if a more complex model may be required, in order to take into account :1) on one side the volatility hump of the IR vol term structure (a 2f model for each term structure ...);2) on the other side FX volatility skew (a SV model for FX ...)As you can see, implementation of such a model becomes unmanageable.Nevertherless, one can add many improvements to a 3f Model:1) Allow piecewise constant volatililities for IR;2) Local Vol or piecewise constant for spot FX rate;Other major pitfalls of the model as for every multi-factor model is the correlation risk.For many other details see the previous threads on technical forum.Hope it's helpful,