Concentration and self-censorship in commercial media

Within a simple model of non-localized, Hotelling-type competitionamong arbitrary numbers of media outlets we characterize qualityand content of media under different ownership structures. Assumingadvertising-sponsored, profit-maximizing outlets, we show that (i) topicssensitive to advertisers can be underreported (self-censored) by alloutlets in the market, (ii) self-censorship increases with the concentrationof ownership, (iii) adding outlets, while keeping the number ofowners fixed, may even increase self-censorship; the latter result relieson consumers' most preferred outlets being potentially owned by thesame media companies. We argue that externalities resulting fromself-censorship could be empirically large.