Sports management

English buys the naming rights to a stadium and the rights in a film; German has one preposition for all of it, and it is an with the dative. Die Namensrechte am Stadion, die Übertragungsrechte an der Liga, ein Anteil an der ausgegliederten Gesellschaft: the thing the right attaches to is where the right sits, so it stands in the dative, and an dem contracts to am. Zu never belongs here, and für, common enough in a headline, gives way to an as soon as the text is a contract. The accusative appears only when something changes hands: a club verkauft die Namensrechte an einen Versicherer, and now an points to the buyer rather than to the stadium. One sentence can carry both cases side by side — Der Verein hat die Namensrechte am Stadion an eine Bank verkauft — and the article is the only thing that tells the reader which an is which.