Fernandinho waived £4 million in loyalty payments to secure his move to Manchester City, according to widespread reports.
Fernandinho completed his move from Shakhtar Donetsk to the Etihad Stadium on Thursday after long negotiations between the two sides.
With City unwilling to meet Shakhtar's £34 million asking price, the 28-year-old Brazil international is said to have sacrificed the bonus payment to allow the Premier League side to pay just £30 million.
ESPN FC had been informed that City had been looking to pay closer to £20 million, while the Ukrainian club had originally sought over £42 million.
Shakhtar, meanwhile, have finalised the €9 million signing of midfielder Wellington Nem from Fluminense on a five-year deal.
"I know this club is used to winning and collecting lots of titles," Wellington, 21, told the club's official website. "That was the main reason I came to Donetsk. Besides, lots of Brazilians play here and have a good reputation."