Manchester United have the biggest transfer losses in Europe in the last decade, according to Swiss-based research institute, CIES Football Observatory.
Since 2012 United have a negative net spend of more than one billion euros, more than rivals Manchester City.
The study revealed that the Red Devils have spent 1.545bn euros on transfers, making 470m euros back in player sales.
Fourteen Premier League clubs are in the top 20.
United broke the Premier League transfer record when they signed Paul Pogba in 2016 for £89.5m and are set to make no return on the midfielder whose contract expires at the end of the season.