The Role of Big Data in Decision-Making: Current Trends in Australia’s Big Four Banks

Abstract—Big Data analytics has emerged as a cornerstone of strategic decision-making in the global banking sector. In Australia, the Big Four Banks, Commonwealth Bank of Australia (CBA), National Australia Bank (NAB), Australia and New Zealand Banking Group (ANZ), and Westpac Banking Corporation, have increasingly adopted Big Data systems to improve customer insights, strengthen risk management, and enhance fraud detection capabilities. This study reviews recent applications and benefits of Big Data-driven decision-making in the Australian banking industry, highlighting collaborations with AI-based analytics providers and developments in openbanking ecosystems. While Big Data has delivered substantial gains in predictive accuracy, operational efficiency, and customer engagement, the sector continues to face challenges related to data quality, governance, privacy, ethics, and system scalability. These issues demonstrate that technology alone is not enough; long-term success requires strong governance, responsible data practices, and alignment with regulatory and organisational objectives. Overall, the findings indicate that effective Big Data integration is reinforcing the sector’s competitive advantage and driving continued innovation in data-driven financial services. Index Terms—Big Data, Decision-Making, Banking Analytics, Applications, Australian Big Four Banks