The interrelation between the fluctuations of stock prices of football clubs and the social media activity of their fans is of major economic interest. The results in this research provide measurable support for the suggestion that financial market activities and the number of tweets are linked in the case of big football clubs. The novelty of the research is to show which daily ratio of tweet counts and their mood can predict the stock market. Based on these findings, sport managers could use social media strategically to build better relationships with consumers and stakeholders.