Félix Tainta, the agent for Athletic Club winger Nico Williams, says Barcelona's move for the Spain international in the summer of 2025 fell apart because the Catalan club could not guarantee his registration. The admission ends months of guessing about what killed a transfer that had filled Spanish front pages. Williams had been Barça's preferred target for the left wing, and the player himself had shown interest in the switch. In Spain, a club cannot field a new signing until league squad-cost rules are satisfied, and Barcelona's chronic squeeze left room for doubt. Without solid guarantees that he would be eligible to play, Tainta steered his client away from the deal. Williams stayed at Athletic Club, where his contract runs well into the next decade. The episode is another marker of how Barcelona's money troubles now reach into the transfer market itself. Tainta's comments are the first clear explanation from inside the negotiation to reach the public.