Received December 18, 2019, accepted February 8, 2020, date of publication February 13, 2020, date of current version February 25, 2020. Digital Object Identifier 10.1109/ACCESS.2020.2973735 The Irruption of Cryptocurrencies Into Twitter Cashtags: A Classifying Solution ANA FERNÁNDEZ VILAS , REBECA P. DÍAZ REDONDO , AND ANTÓN LORENZO GARCÍA Information and Computing Lab, AtlantTIC Research Center, School of Telecommunications Engineering, University of Vigo, 36310 Vigo, Spain Corresponding author: Ana Fernández Vilas (
[email protected]) This work was supported in part by the European Regional Development Fund (ERDF), in part by the Galician Regional Government through the Atlantic Research Center for Information and Communication Technologies (AtlantTIC), and in part by the Spanish Ministry of Economy and Competitiveness through the National Science Program under Grant TEC2014-54335-C4-3-R and Grant TEC2017-84197-C4-2-R. ABSTRACT There is a consensus about the good sensing characteristics of Twitter to mine and uncover knowledge in financial markets, being considered a relevant feeder for taking decisions about buying or holding stock shares and even for detecting stock manipulation. Although Twitter hashtags allow to aggregate topic-related content, a specific mechanism for financial information also exists: Cashtag (consisting of the company ticker preceded by $) is a supporting mechanism to track financial tweets referring to a company listed in a stock market. However, according to our experiments and due to the lack of conventions in cashtags usage, the irruption of cryptocurrencies has resulted in a significant degradation on the cashtag-based aggregation of posts. Unfortunately, Twitter' users may use homonym tickers to refer to cryptocurrencies and to companies in stock markets, which means that filtering by cashtag may result on both posts referring to stock companies and cryptocurrencies.