With a net cost of 1 billion euros, Manchester United leads the league of transfer losses.

Sports

On Monday, Manchester United returned to the top of the leaderboard, but not in the way they had hoped, as they were declared the club with the most transfer losses in the last decade, having spent more than one billion euros ($1.14 billion) on players.
According to the CIES Football Observatory, a Swiss-based independent research body, United has spent 1.075 billion euros on transfers since 2012, with 1.545 billion spent on transfers and 470 million returned in player sales.

United broke the Premier League transfer record when they paid 89.5 million pounds ($120.89 million) for Paul Pogba in 2016, but they are unlikely to recoup their investment in the French midfielder, who has fallen short of expectations and is free to leave when his contract expires at the end of the season.
Anthony Martial, who cost the club 36 million pounds in 2015, and Donny van de Beek, who cost the club 40 million pounds in 2020, are two more expensive but unsuccessful signings. Last month, both players went on loan to Sevilla and Everton, respectively.

Manchester City, their local rivals, came in second with a net spend of 984 million euros, spending more than United (1.699 billion) but bringing in 715 million in sales.
With a net spend of 941 million, Paris St Germain came in third.
Barcelona came in fourth with a net spend of 650 million, despite the fact that the Catalans have been in financial trouble in recent years due to an inflated salary bill that prompted them to sell all-time leading scorer Lionel Messi.
However, whereas PSG, City, and Barcelona have plenty of trophies to show for their decade-long excesses, United has mainly underperformed on the field, particularly after serial-winning manager Alex Ferguson resigned in 2013.

They have only won one league title since 2012, compared to five for City, seven for PSG, and five for Barcelona. United’s most recent trophy came in 2017, as Jose Mourinho led the team to victory in the Europa League.
They are now fourth in the Premier League, 19 points behind leaders City, and were knocked out of the FA Cup on Friday by Middlesbrough of the Championship (second tier).