(Reuters) - Spain's antitrust watchdog CNMC fined Mediaset Espana <TL5.MC> and Atresmedia <A3M.MC> a total of 77.1 million euros (£66.31 million) for anti-competitive behaviour related to the marketing of television advertising, the regulator said on Wednesday.
The fine for Mediaset's Spanish unit was 38.9 million euros and 38.2 million euros for Atresmedia, it added.
Both Mediaset Espana and Atresmedia developed a strategy in the sale of television advertising which resulted in a market share of over 85%, the Spanish watchdog said.
To achieve this, both companies imposed a high quota on advertisers, forcing them to spend a significant part of their advertising budget on the broadcasters, the regulator said.
This way they limited the capacity of other television channels to capture advertising revenue, it added.
Spain's competition regulator said both broadcasters are required to modify their commercial strategy within three months.
(Reporting by Anita Kobylinska; Editing by Jose Elias Rodriguez and Ashifa Kassam)