This paper reports about research into the use of sentiment
analysis on social media in order to predict a company’s
short term performance. As a measure for the short term
performance, the stock price of a company is used. The
sentiment is extracted from a large corpus of tweets mentioning
twenty large companies and a few techniques of
extracting sentiment are reviewed. We find that for sentiment
analysis a Naive Bayes classifier trained with data
very similar to the corpus performs best. We use the Naive
Bayes classifier to extract the sentiment from tweets. Together
with the stock prices of twenty companies, we train
various supervised machine learning models. We find that
there is a combination of data where the accuracy of a
classifier is 65,5%, but most other cases appear to be as
bad as an algorithm that classifies randomly.