Vliv reklamních výdajů na zisky firem v oligopolu s dominantní firmou s důrazem na Tullockův model a duopolní charakter konkurenčního lemu

This bachelor’s thesis examines the cross‑effects of advertising expenditures on firms’ sales in an oligopoly with a dominant firm, using the video game console market as an example, where Sony acts as the dominant firm and Nintendo together with Microsoft form a duopolistic competitive fringe. The analytical framework is based on duopoly and oligopoly models from game theory, the Tullock contest model and the literature on generic and brand advertising. The empirical part uses annual data on sales and advertising expenditures of Nintendo and Microsoft in the period 2012–2024, supplemented by the number of major game titles and the introduction of new consoles, and employs multivariate regression models and a log‑linear specification derived from the Tullock model. The results show that the absolute level of Nintendo’s advertising expenditures acts as generic advertising and is associated with higher Microsoft sales, whereas their year‑on‑year growth has the character of brand advertising and leads to a statistically significant decline in Microsoft’s sales. Microsoft’s advertising expenditures do not have a statistically significant effect on Nintendo’s sales. The estimated Tullock model approximates the ratio of the two firms’ advertising expenditures relatively well, whereas Friedman’s model of optimal advertising expenditures systematically overestimates the actual expenditures and exhibits large errors, which suggests that it is unsuitable for this market. The thesis shows that even a relatively simple Tullock model can capture the structure of advertising effort in a duopoly with acceptable accuracy.