Manchester United named America 's most valuable club by Forbes for sixth straight year . Real Madrid come second on list , with Arsenal third and Barcelona fourth . Top 20 clubs saw their average value rise to $ 800 million from $ 691 million .
Manchester United named world 's most valuable club by Forbes for sixth straight year . Real Madrid come second on list , with Arsenal third and Barcelona fourth . Top 20 clubs see their average value decline to $ 632 million from $ 691 million .