Local Volatility vs. Stochastic Volatility

Question

Are there any empirical observations or practices when to prefer Local Volatility Model for pricing over Stochastic Model or vice versa?

Answer 1

There is another reason why Stoc Vol Models should be usually prefered to Local vol Models, this reason is explained in the Hagan et al. paper "Managing smile Risk" about SABR process and is in simple terms the fact that "smile dynamics" is poorly predicted by local vol models leading to bad Hedging of exotic options.

Anyway Local Vol models have the good feaute to be "arbitrage free" (at the begining) and I think that some link between both approach can be achieved by Markovian Projection Method.for this you can have a look at V. Piterbarg's paper on the subject and the references therein.

Regards

Answer 2

For pricing, there are a few products whose prices are sensitive to the forward smile and when you compute that with just local vol, it is not realistic.

So if you are a seller, you go to the next church and find something that looks kindof reasonable, and that kind of can reconstruct a reasonnable forward smile structure.

The game in pricing is to not sell for 0 something that you know can't be 0. Especially if 90% of the product price comes from this particular effect.

For hedging one could try to add this and that dependency, but the chance are you are off big time on 2 other things.

Answer 3

For pricing and hedging a portfolio of vanilla options, stochastic volatility is almost always preferable to local volatility since empirically it more accurately captures the evolution of the smile.