This case pits SoundExchange, a nonprofit entity, charged with the responsibility of collecting royalties for performing artists and copyright owners of music, against Muzak, a company that supplies digital music channels to satellite television networks who, in turn, sell to subscribers. SoundExchange sued Muzak under the Copyright Act in district court, claiming that Muzak underpaid royalties owed. The district court dismissed SoundExchange’s complaint. (From the point of view of classic administrative law, the Register of Copyrights, to which we normally are obliged to defer, plays a rather unusual role.) Although the case is close – the controlling statute is dreadfully ambiguous – we conclude that SoundExchange has the better position, and therefore reverse the district court.