Manchester United have had an improved £50m bid rejected by Crystal Palace for right-back Aaron Wan-Bissaka, according to Sky Sports.
It is understood the bid was worth an initial £35m, with additional payments totalling to £15m.
Palace are understood not to be happy with the structure of the proposed deal, but it is believed they would accept £50m up front for the England U21 international.
Although Wan-Bissaka favours a move to Old Trafford, he has not put in a transfer request or agitating for the switch.
United failed with their first offer of £40m last week, with Palace under no pressure to sell the 21-year-old.
Wan-Bissaka, who featured 39 times in all competitions last season, has three years remaining on his contract at Selhurst Park.
United manager Ole Gunnar Solskjaer is keen to bring in a right-back this summer following the departure of club captain Antonio Valencia.