Fulham's 3-2 victory over QPR on Monday night could end up costing Martin Jol's club £500,000.
When Fulham sold Bobby Zamora to Rangers for £4million in January 2012 they negotiated a £500,000 bonus for every year QPR stayed in the Premier League during the striker's two-and-a-half-year contract at Loftus Road.
Fulham got their cash last season as QPR staved off relegation on the last day of the campaign to finish 17th, but Monday's west London derby defeat at Craven Cottage has left Rangers' hopes of survival in ruins.
QPR are second from bottom, seven points adrift of safety with only seven games left to salvage their top-flight status.