Manchester United have lost over 10 per cent in value over the last 12 months.
United's horror season has seen the club's value plummet by 11 per cent, says the Daily Mail.
Real Madrid top the list, with the Spanish giants being worth £2billion - just ahead of bitter rivals Barcelona - who have added 23 per cent to their value as a club last year.
The top 10 compiled by Forbes sees Premier League champions elect Manchester City as one of the highest gainers - adding 25 per cent to their value, coming in at £508million.
They're behind English rivals Arsenal and Chelsea, who are valued at £767million and £511million respectively.
THE FORBES TOP 10 MOST VALUABLE CLUBS
1) Real Madrid - £2billion (Up 4%)
2) Barcelona - £1.9billion (Up 23%)
3) Manchester United - £1.65billion (Down 11%)
4) Bayern Munich - £1.1billion (Up 41%)
5) Arsenal - £767million (Zero Change)
6) Chelsea - £511million (Down 4%)
7) Manchester City - £508million (Up 25%)
8) AC Milan - £504million (Down 9%)
9) Juventus - £501million (Up 22%)
10) Liverpool - £407million (Up 6%)