Pompey are guaranteed a windfall from Adam Webster's sale to Bristol City.
The former Blues defender completed his switch to the Robins from Ipswich today, reportedly for an initial fee of £3.5m.
And it means Pompey will receive 20 per cent of the profit from the transfer.
Webster moved to the Tractor Boys from Fratton Park in June 2016 for £750,000.
In his Portman Road contract there was a 20 per cent sell-on clause inserted.
As a result, it means Webster's departure from Ipswich to Bristol City will earn the Blues £550,000 from the £2.75m profit Paul Hurst's side will net.
Adam Webster. Picture: Joe Pepler
Webster will link-up with former Pompey midfielder Marlon Pack at Ashton Gate.