Self-Organizing Maps (SOM) are a special form of Neural Networks that use unsupervised learning and auto-classification of data. Therefore, SOM is a very flexible algorithm which is in particular well-suited to identify unexpected structures in complex (and multidimensional) data sets. We use...

A popular theory of markets is that they are efficient: all available information is deemed to provide an accurate valuation of an asset at any time. In this paper, we consider how the content of market-related news articles contributes to such information. Specifically, we mine news articles...

The efficient market hypothesis states that the market incorporates all available information to provide an accurate valuation of the asset at any given time. However, most models for forecasting the return or volatility of assets completely disregard the arrival of asset specific news (i.e.,...