Borussia Dortmund have warned Manchester United they won't accept any special clauses in Jadon Sancho's transfer deal.
United acted on their long-term interest in Sancho by submitting a formal bid for the England winger earlier this week.
United chiefs have agreed personal terms with the 21-year-old, who came close to moving to Old Trafford last summer.
But their £67million offer was rejected by Dortmund, who value the former Manchester City academy prospect at £81.5million.
Adding to their grievances over the up-front fee, the Bundesliga club are concerned over the nature of the add-ons in United's initial offer.
The Athletic reports Dortmund are not interested in any add-ons they deem to be unrealistic.
For example, they have rejected a Ballon d'Or clause which would have been activated if Sancho finished in the top three at the prestigious annual awards ceremony.
Instead, the report adds Dortmund will push for instalments based on United's future income based on the success of the team rather than Sancho individually.
