Open AccessQuantifying impact and response in markets using information filtering networks
Author(s) -
Isobel Seabrook,
Fabio Caccioli,
Tomaso Aste
Publication year - 2022
Publication title -
journal of physics. complexity
Language(s) - English
Resource type - Journals
ISSN - 2632-072X
DOI - 10.1088/2632-072x/ac6721
Subject(s) - econometrics , covariance , economics , diversification (marketing strategy) , stock market , shock (circulatory) , multivariate statistics , stock (firearms) , financial economics , monetary economics , mathematics , statistics , business , geography , medicine , context (archaeology) , archaeology , marketing
We present a novel methodology to quantify the `impact' of and `response' to market shocks. We apply shocks to a group of stocks in a part of the market, and we quantify the effects in terms of average losses on another part of the market using a sparse probabilistic elliptical model for the multivariate return distribution of the whole market. Sparsity is introduced with an $L_0$-norm regularization, which forces to zero some elements of the inverse covariance according to a dependency structure inferred from an information filtering network. Our study concerns the FTSE 100 and 250 markets and analyzes impact and response to shocks both applied to and received from individual stocks and group of stocks. We observe that the shock pattern is related to the structure of the network associated with the sparse structure of the inverse covariance of stock {\color{black} log-returns}. Central sectors appear more likely to be affected by shocks, and stocks with a large level of underlying diversification have a larger impact on the rest of the market when experiencing shocks. By analyzing the system during times of crisis and comparative market calmness, we observe changes in the shock patterns with a convergent behavior in times of crisis.