The empirical literature on mergers, market power and cooperation in differentiated markets has mainly focused on methods
relying on output and/or panel data. In contrast to this literature we propose an approach to analyse cooperative behaviour
among a group of firms only by making use of information on the spatial structure of a horizontally differentiated market.
Using spatial econometrics techniques we focus on differences in the pricing behaviour between different groups of firms,
i.e., alliance and stand-alone firms. We apply this method to the market for ski lift tickets using a unique data set on ticket
prices and detailed resort-specific characteristics covering all ski resorts in Austria. We show that prices of ski resorts
forming alliances are higher and increase with the size and towards the spatial center of an alliance. Interaction in pricing
is higher within than outside alliances. All results are in line with the findings of theoretical models on non-competitive
pricing behaviour in horizontally differentiated markets.