1. Manchester United
Total debt: $569million
The Glazer family took full ownership of Manchester United in 2005, with the use of various loans which were secured against the club's assets.
Their takeover at Old Trafford resulted in the accruement of debts to the tune of 18 per cent of the total valuation of $3.165billion.
Manchester United are ranked second on Forbes' rich list - behind only Real Madrid - but have a significantly larger overhead ($569million), which is more than three times the Spanish giants.