Credit card transaction data contains a vast amount of valuable information that can indicate consumer behaviour patterns and mark out human mobility. In this study we analyse the transactions carried out by a sample of 10.000 Istanbul-based customers of a Turkish bank to scrutinize expenditures incurred out of Istanbul. In our preliminary descriptive analysis, we examine the relation between demographic attributes and spending measures, as well as investigate the extent to which the population and the number of points of interest imply higher or lower credit card expenditure by visitors. We develop a methodology to extract tourist trips from consecutive credit card transactions. Subsequently, we implement a hierarchical clustering method to evaluate what the purpose of these trips might have been. Our results indicate 5 clusters of purpose: ’Leisure’, ’Business’, ’Acquisition’, ’Visiting Friends and Relative’ and ’Package Holiday’. The same clustering method is applied to segment provinces of Turkey based on which product and service categories visitors prefer. We deploy a number of predictive models to estimate tourist expenditure and whether a person would embark on a trip in the upcoming months. The predictive power of these models are generally moderate; nevertheless, several of the most useful predictors are behavioural or are related to previous trips, factors that have not been considered in literatur
