Real Madrid is football's biggest moneymaker for the 10th straight year, while Manchester United has risen to second in the rankings by maintaining its commercial growth during its worst-ever Premier League campaign.
In the Football Money League compiled by accountancy firm Deloitte, German champion Bayern Munich remained third but Barcelona dropped from second to fourth during its trophyless 2014.
In the 2013-2014 financial year, Real generated 549.5 million euros ($752 million on June 30). United brought in 433.2 million pounds ($740 million on June 30), which equated to 518 million euros during the financial year. The current exchange rate would put United top on 566 million euros.
Bayern generated 487.5 million euros, Barcelona 484.6 million euros and Paris Saint-Germain 474.2 million euros.
Overall, the revenue of the world's top 20 clubs, which are all European and dominated by eight from the English Premier League, grew 14 percent year-on-year to 6.2 billion euros ($8.5 billion). The only team to feature from outside the major leagues - England, Spain, Italy, Germany and France - is Turkish champion Galatasaray at 18th with a turnover of 161.9 million euros.
Although Real missed out on the Spanish title in 2013-14, the team ended its 12-year wait to be crowned European champions for the 10th time in May.
''The club's continued success on the field is complemented by its financial strength and their accomplishment emphasizes their position as the most successful European club side of all time,'' said Dan Jones, a partner in Deloitte's sports division.
But Real's supremacy is being threatened by Manchester United, despite the 20-time English champions lacking any UEFA cash in its 2014-15 accounts after the failure to qualify for Europe during David Moyes' ill-fated season in charge. There is a recovery under Louis van Gaal, with United fourth in the Premier League.
''Despite a poor on-pitch season in 2013-14, United's commercial strategy of securing global and regional partners is delivering substantial growth,'' Deloitte senior manager Austin Houlihan said. ''Commercial revenue has grown 83 percent in the last three years.
The growth in the value of Premier League television rights led to every team in the topflight reporting record revenue in 2013-14, Deloitte said.
2013-14 positions and revenue in brackets. All figures in millions of euros.
1 (1), Real Madrid, 549.5 (518.9).
2 (4), Manchester United, 518.0 (423.8).
3 (3), Bayern Munich, 487.5 (431.2).
4 (2), Barcelona, 484.6 (482.6).
5 (5), Paris Saint-Germain, 474.2 (398.8).
6 (6), Manchester City, 414.4 (316.2).
7 (7), Chelsea, 387.9 (303.4).
8 (8), Arsenal, 359.3 (284.3).
9 (12), Liverpool, 305.9 (240.6).
10 (9), Juventus, 279.4 (272.4).
11 (11), Borussia Dortmund, 261.5 (256.2).
12 (10), AC Milan, 249.7 (263.5).
13 (14), Tottenham, 215.8 (172.0).
14 (13), Schalke, 213.9 (198.2).
15 (20), Atletico Madrid, 169.9 (120.0).
16 (new), Napoli, 164.8 (116.4).
17 (15), Inter Milan, 164.0 (164.5)
18 (16), Galatasaray, 161.9 (157.0).
19 (new), Newcastle, 155.1 (111.9).
20 (new), Everton, 144.1 (100.8).
Only the European champions stand ahead in terms of income while Barcelona by contrast are struggling to keep pace financially with their Spanish rivals, United and Bayern Munich.
The money league compiled by Deloitte sees Real established as the world's richest club with revenues of 549.5million euros ((hash)459m) for the 10th year in succession while United are on 518m euros, Bayern 487m and Barcelona 484m.
''A season that saw Manchester United finish in their lowest league position since the start of the Premier League era actually saw the Red Devils reclaim second spot in the money league,'' Jones said.
''Their commercial growth... continues to yield record-breaking deals. If the club can regain their Champions League status for the 2015/16 season, there is a strong possibility they will also regain top spot in our money league for that season.''
United's hopes of overtaking Real have also been boosted by the strength of the pound against the euro.
The money league sees Manchester City remain in sixth position behind Paris St Germain, with Chelsea and Arsenal hold on to their seventh and eighth places and Liverpool moves up to ninth.
Indeed, almost half of the top 30 richest clubs are now made up of Premier League sides and that figure is likely to increase.
Jones added: ''It is with great anticipation that we wait to see what the new round of Premier League broadcast deals, expected to be agreed in 2015, will yield. With the market expectation that another significant increase will occur, it is likely that the money league will have a strongly English appearance in the coming years.''
The Deloitte report highlights the decline of Italian clubs in terms of finances. In 2001 Italy had five clubs in the top 10 and only Juventus, which significantly has built a new stadium, remains there now in 10th position.
It also shows the continuing value to the Spanish clubs of negotiating their own broadcast rights. Real earned more than twice the sum of Atletico Madrid in broadcast income, despite its city rivals winning the Spanish league and reaching the final of the Champions League.
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