TY - UNPD A1 - Anese, Gianluca A1 - Corazza, Marco A1 - Costola, Michele A1 - Pelizzon, Loriana T1 - Impact of public news sentiment on stock market index return and volatility T2 - SAFE working paper ; No. 322 N2 - Recent advances in natural language processing have contributed to the development of market sentiment measures through text content analysis in news providers and social media. The effectiveness of these sentiment variables depends on the imple- mented techniques and the type of source on which they are based. In this paper, we investigate the impact of the release of public financial news on the S&P 500. Using automatic labeling techniques based on either stock index returns or dictionaries, we apply a classification problem based on long short-term memory neural networks to extract alternative proxies of investor sentiment. Our findings provide evidence that there exists an impact of those sentiments in the market on a 20-minute time frame. We find that dictionary-based sentiment provides meaningful results with respect to those based on stock index returns, which partly fails in the mapping process between news and financial returns. T3 - SAFE working paper - 322 KW - Public financial news KW - Stock market KW - NLP KW - Dictionary KW - LSTM neural networks KW - Investor sentiment KW - S&P 500 Y1 - 2021 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/63339 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-633392 UR - https://ssrn.com/abstract=3937901 IS - October 2021 PB - SAFE CY - Frankfurt am Main ER -