Barcelona will pay Santos an additional €2 million if Neymar has a top-three finish in the Fifa Ballon d'Or in the next five years, according to documents received by Radio Globo.
The Catalans secured the services of the Brazil international in a deal worth €57m, but Santos obtained only €9.35m of the fee.
A hefty €40m was paid in commission to other parties including Neymar's father, while the remaining €7,65m was split between two companies which owned part of his registration, Teisa Group and DIS.
Santos could earn an extra €2m, though, if the 21-year-old enjoys success at the highest level and makes it onto the podium of the Ballon d'Or between now and 2017.
Neymar had to settle for 13th spot in the 2012 Fifa Ballon d'Or election, while finishing 10th in the 2011 vote.
He will be hopeful of doing better in 2013, though, after earning a transfer to Barcelona and guiding Brazil to Confederations Cup glory this summer.
Barca team-mate Lionel Messi has won the inaugural three editions of the Fifa Ballon d'Or and scooped the World Player of the Year accolade in 2009.