This research aims to advance understanding of how investments in Information Technologies (IT) impact on firm performance by developing and testing an advanced model of IT business value. Research so far has provided incomplete and controversial evidence as to the difference that IT investments made on firms’ performance. This research adopts a novel multi-method research approach that combines a study of stock market returns on over 10,000 IT investment announcements between 1990 and 2009 in Australia and in-depth case studies of value creation after IT deployment in selected firms. The research aims to provide a more refined model of IT business value and an extensive analysis of IT investments impact on firms’ market value in Australia. The advanced model of the business value of IT investments will fill the gap in the literature and contribute to better understanding of the relationships between IT investments and firm performance. The model is expected to improve understanding of numerous factors relevant for assessing and predicting the business value of IT investments and thereby assist business and IT managers in making better informed IT investment decisions.