Nowcasting networks

Abstract

We devise a neural network-based compression/completion methodology for financial nowcasting. The latter is meant in a broad sense, encompassing completion of gridded values, interpolation and outlier detection, in the context of financial time series of curves or surfaces. (It is also applicable in higher dimensions, at least in theory.) In particular, we introduce an original architecture amenable to the treatment of data defined at variable grid nodes (by far the most common situation in financial nowcasting applications, where principal component analysis (PCA) and classical autoencoder methods are not applicable). This is illustrated by three case studies on real data sets. First, we introduce our approach on repurchase agreement curves data (with a moving time-to-maturity as calendar time passes). Second, we show that our approach outperforms elementary interpolation benchmarks on an equity derivative surfaces data set (again, with a moving time-to-maturity). We also obtain a satisfying performance for outlier detection and surface completion. Third, we benchmark our approach against PCA on at-the-money swaption surfaces redefined at constant expiry/tenor grid nodes. Our approach is then shown to perform as well as (even if not obviously better than) the PCA (which, however, is not applicable to the native, raw data defined on a moving time-to-expiry grid).