Premier League clubs posted record revenues of £3.6bn in 2015-16, but still struggled to make a profit.
The 20 top-flight English teams made a pre-tax loss of £110m, after two consecutive seasons in the black, according to figures from Deloitte.
Clubs saw increased player expenditure, operating costs and one-off charges.
The two Manchester clubs' revenues increased by a total of £160m - roughly half of the total revenue growth recorded by the Premier League clubs.
"The 2015-16 season saw Premier League clubs grow revenues by almost 10%... with the two Manchester clubs alone responsible for more than 50% of the increase," said Dan Jones, head of the Sports Business Group at Deloitte.