Researchers built the world’s first public inventory of ownership for 9,761 digital news outlets in 77 countries, using data from Wikipedia and Wikidata. Using this inventory, they calculated traffic‑weighted Herfindahl–Hirschman Index (HHI) concentration scores for each country. The results show that media markets vary widely, with some nations dominated by a handful of owners and others more evenly split.

Applying the same ownership map to the ways AI systems cite news, the study compared AI‑citation concentration to ordinary audience traffic. Across seven AI models, including popular tools like Gemini, Copilot, and Google AI Overviews, the median amplification of concentration ranged from 1.23‑x to 2.08‑x. That is, for a given country, AI citations were concentrated on a narrower set of outlets than the outlets actually visited by readers.