Highlights Europe's top football clubs collectively lost more than ?1.6 billion ($2 billion) in 2010 and their debts keep rising ahead of planned rules to sanction clubs for overspending, according to UEFA research published Wednesday. Skepticism has grown over UEFA's willingness to take on big-spending clubs such as Premier League leader Manchester City, whose owners from Abu Dhabi funded a 194.9-million-pound (then $318 million) loss for 2010-11, the final season before FFP took effect. UEFA acknowledged that 13 clubs, including several from England, would have failed its break-even tests on their 2010 accounts. The clubs were not identified. Financial fair play (FFP) rules allow clubs to make a total loss of ?5 million ($6.5 million) in the first assessment period, or up to ?45 million ($58 million) if a wealthy owner makes a one-off donation to wipe out losses. UEFA will phase in tighter monitoring rules in future years.