Phillipe Coutinho — Barcelona €135M Transfer

Phillipe Coutinho ranks as Barcelona's most disastrous €135 million outlay, a fee that exceeded the average La Liga team's annual budget. The Brazilian playmaker, signed from Liverpool in January 2018, managed just 21 league goals across three seasons before two loan spells and a permanent exit to Aston Villa for a mere €20 million—a staggering 85% drop in value. His Camp Nou tenure yielded only one Copa del Rey, and his creative output plummeted 40% compared to his Liverpool peak, per Opta.