West Ham face a £4m bill for their six-month loan of Manchester United midfielder Jesse Lingard.
The Daily Mail says the 28-year-old England international was confirmed as David Moyes' latest acquisition on Friday as he joins the East London club until the end of the season.
And it has now been revealed that as well as the £1.5m loan fee and £100,000 per week wages, United have also negotiated a £500,000 bonus.
The clause will be triggered if the Hammers qualify for Europe this season.
The Irons host Liverpool later today.
