Cross-ownership has gained more attention since the Millennium. The effects of cross-ownership have been incorporated into standard game theoretical models, altering the traditional concentration measures and hence also the relationship between concentration and profitability. Empirical research on the effects of crossownership on concentration and profitability is limited. This article compares the traditional concentration index with the one modified for cross-ownership in the Finnish newspaper publishing industry. With a dataset that covers all daily newspaper publishers between years 1950 and 2016, we show that cross-ownership is reflected in the modified empirical concentration measures. We also show how acknowledging the two-sidedness of a market affects the profitability measures originally developed for traditional markets.