Sporting Lisbon received a fee of just £6.5m from Manchester United for Cristiano Ronaldo 11 years ago, according to the club's former communications director, Carlos Severino.
United acted quickly to secure the services of the prodigious young Ronaldo in 2003 and paid a reported fee of around £13m to bring the player of Old Trafford.
Over the next six years, the teenager morphed into the transcendent talent he stands as today under United's guidance, winning three Premier League titles, an FA Cup and a Champions League before joining Real Madrid for a then world record £80m in 2009.
Sporting's shares of the profits, however, were a mere fraction of that fee, according to Serevino who suggests half of the sum originally paid by United went to a third party.
In an interview with Publico, Severino, who served at Sporting between 1998 and 2006, said: "Sporting received just €8.25m [£6.5m] for the sale to Manchester United for the player who is currently the best in the world. It was poor business.
"Manchester United paid €17.5m [£13.7m] for Ronaldo, but €2.5m [£2m] was used to pay commissions and €5.25m [£4.1m] went to fund [third-party ownership group] First Portuguese Football Players, which owned 35% of the player's rights."
Serevino added Ronaldo was valued at €1.8m as a 16-year-old by Sporting, prompting FPFP to purchase 35% of his rights for just €627,000.
The issue of third-party ownership in Portugal also dominated Marcos Rojo's transfer from Sporting to United during the summer transfer window. It was revealed 75% of Rojo's economic rights were held by investment group Doyen Sports prior to the move, a stake that entitled it to three quarters of the £16m transfer fee the Argentine fetched.
Sporting are still in a dispute with the Malta-based group over the transfer fee with club president Bruno de Carvalho declaring the original agreement between Doyen and the club was invalid due to Doyen's attempts to take control of decisions regarding the player's future, a direct violation of rules handed down to third-party groups.
Doyen has repeatedly denied any wrongdoing despite strong allegations of interference made by Sporting in the summer and the dispute continues.