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Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19

This study examines the use of deep learning to identify and characterise anomalous events and their preceding weak signals in equity price data. Particular interest is placed on Gray Rhino events, indicated by the presence of progressively stronger signals prior. The market behaviour prior to and d...

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Main Author: Clarke, Keegan G
Other Authors: Huang, Chun-Sung
Format: Thesis
Language:English
Published: Department of Finance and Tax 2025
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access_status_str Open Access
author Clarke, Keegan G
author2 Huang, Chun-Sung
author_browse Clarke, Keegan G
Huang, Chun-Sung
author_facet Huang, Chun-Sung
Clarke, Keegan G
author_sort Clarke, Keegan G
collection Thesis
description This study examines the use of deep learning to identify and characterise anomalous events and their preceding weak signals in equity price data. Particular interest is placed on Gray Rhino events, indicated by the presence of progressively stronger signals prior. The market behaviour prior to and during the COVID-19 pandemic on G-20 equity markets provides a useful context to this end. Existing literature has examined the effects of the pandemic on these markets but has yet to provide conclusive insights into the development of the major equity crash. We compare the existing literature concomitantly to our rigorous application of event study methodology, identifying the presence and effects of signals prior to the market crash. In addition, we develop and deploy a novel Anomaly Characterisation Process (ACP). The ACP utilises an ARIMA time series model to transform equity price time-series for the extraction of relevant information, whereby subsequent fits of GJR-GARCH and deep-undercomplete-autoencoder models are deployed. Resultantly, measures of dispersion and atypicality are produced which allow for effective and clear characterisation of the degree of typicality of the equity prices and their movements. This innovative method demonstrates efficacy in detecting both point and contextual anomalies. When applied in the context of COVID-19, the findings suggest that different event types can be distinguished successfully with this novel approach through the identification of weak signals. Notably, these insights of the ACP in conjunction with those of the event study suggest that the COVID-19 market crash is consistent with a Gray Rhino event and not a Black Swan event. We briefly demonstrate that these insights can be used by market participants to improve risk-adjusted returns via ACP-informed risk-mitigation techniques.
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institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:32:33.381Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2025
publishDateRange 2025
publishDateSort 2025
publisher Department of Finance and Tax
publisherStr Department of Finance and Tax
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/40838 Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19 Clarke, Keegan G Huang, Chun-Sung This study examines the use of deep learning to identify and characterise anomalous events and their preceding weak signals in equity price data. Particular interest is placed on Gray Rhino events, indicated by the presence of progressively stronger signals prior. The market behaviour prior to and during the COVID-19 pandemic on G-20 equity markets provides a useful context to this end. Existing literature has examined the effects of the pandemic on these markets but has yet to provide conclusive insights into the development of the major equity crash. We compare the existing literature concomitantly to our rigorous application of event study methodology, identifying the presence and effects of signals prior to the market crash. In addition, we develop and deploy a novel Anomaly Characterisation Process (ACP). The ACP utilises an ARIMA time series model to transform equity price time-series for the extraction of relevant information, whereby subsequent fits of GJR-GARCH and deep-undercomplete-autoencoder models are deployed. Resultantly, measures of dispersion and atypicality are produced which allow for effective and clear characterisation of the degree of typicality of the equity prices and their movements. This innovative method demonstrates efficacy in detecting both point and contextual anomalies. When applied in the context of COVID-19, the findings suggest that different event types can be distinguished successfully with this novel approach through the identification of weak signals. Notably, these insights of the ACP in conjunction with those of the event study suggest that the COVID-19 market crash is consistent with a Gray Rhino event and not a Black Swan event. We briefly demonstrate that these insights can be used by market participants to improve risk-adjusted returns via ACP-informed risk-mitigation techniques. 2025-01-28T09:55:56Z 2025-01-28T09:55:56Z 2024 2025-01-28T08:24:48Z Thesis / Dissertation Masters MCom http://hdl.handle.net/11427/40838 eng application/pdf Department of Finance and Tax Faculty of Commerce University of Cape Town
spellingShingle Clarke, Keegan G
Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19
thesis_degree_str Master's
title Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19
title_full Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19
title_fullStr Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19
title_full_unstemmed Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19
title_short Using deep learning to characterise weak signals in global equity markets: a case study of COVID-19
title_sort using deep learning to characterise weak signals in global equity markets a case study of covid 19
url http://hdl.handle.net/11427/40838
work_keys_str_mv AT clarkekeegang usingdeeplearningtocharacteriseweaksignalsinglobalequitymarketsacasestudyofcovid19