Deep Learning Interpretability for Rough Volatility

Abstract

Deep learning methods have become a widespread toolbox for pricing and calibration of financial models. While they often provide new directions and research results, their 'black box' nature also results in a lack of interpretability. We provide a detailed interpretability analysis of these methods in the context of rough volatility-a new class of volatility models for Equity and FX markets. Our work sheds light on the neural network learned inverse map between the rough volatility model parameters, seen as mathematical model inputs and network outputs, and the resulting implied volatility across strikes and maturities, seen as mathematical model outputs and network inputs. This contributes to building a solid framework for a safer use of neural networks in this context and in quantitative finance more generally.

Keywords: rough volatility, deep learning, interpretability, Shapley values, surrogate models, option pricing

JEL Classification: C45, C63, G13