Beyond the Smile: A Hybrid Convolutional VAE for Crypto Volatility Surfaces
This study addresses the challenge of reconstructing and forecasting cryptocurrency implied volatility surfaces under significant structural data sparsity. The authors propose a hybrid approach that integrates a convolutional variational autoencoder (CVAE) with deterministic maturity routing to fit the volatility smile quadratically. This work presents the first application of CVAE to crypto volatility surface modeling, enabling joint cross-asset training on Bitcoin (BTC) and Ethereum (ETH) and uncovering a shared latent manifold structure between them. The method simultaneously enforces calendar and butterfly no-arbitrage constraints, achieving a root mean squared error (RMSE) of 0.83 volatility points at 50% missingness—eight times lower than conventional smile-fitting techniques—and demonstrates superior capability in detecting market anomalies compared to existing approaches.