In a ruling last year in a separate case filed against Anthropic by book authors, a federal judge ruled that AI training itself is covered by fair use — a major legal win for the AI industry. In the wake of that ruling, UMG and the music publishers moved to update their lawsuit with new allegations that Anthropic had relied on millions of books containing sheet music it illegally downloaded from file-sharing sites. But that bid to amend the case was denied by the judge as procedurally improper. “Publishers recently discovered that defendants downloaded by torrenting an enormous number of unauthorized copies of publishers’ works from illegal shadow libraries to avoid paying for those works,” the publishers write. We believe this will be one of the largest (if not the single-largest) non-class action copyright cases filed in the U.S.”