Barcelona missed out on over 7 million ($7.2m) as part of Nico Gonzlez's 60m ($62m) transfer to Manchester City after Porto exercised a clause which reduced how much the Catalan club would receive.
Gonzlez, 23, joined Porto from Bara for an initial 8.5m in 2023, with the LaLiga side maintaining an option to re-sign the midfielder for 30m and also due 40% of the capital gains of any future transfer.
However, prior to Gonzlez's move to City, Porto paid 3m to exercise a clause which reduced Bara's cut of any fee to 20% and also cancelled their option to re-sign him.
"The club exercised in advance an option to purchase 20% of the capital gains from a transfer for a value of 3m," the Portuguese side explained in a statement.
"That also cancelled the option to re-sign the player that Barcelona had for a value of 30m, exercisable until June. 30, 2025.
"Bara retained the right to 20% of the capital gains."
In total, therefore, Bara made 13.32m from Gonzlez's move to City on Monday, in addition to the 8.5m paid by Porto two years ago.
They received 3m from Porto for 20% of the capital gains and then 10.32m for their 20% stake in the capital gains on any fee, bringing the total income from Gonzlez's two moves to 21.72m.
However, the clause exercised by Porto denied them of an additional 7.3m or, alternatively, the chance to re-sign Gonzlez and potentially move him onto City themselves for an even bigger windfall.
Gonzlez joined Bara's academy in 2013 and went on to make 37 first team appearances before joining Porto, via a loan spell with LaLiga side Valencia, on a permanent deal.