Many of the world's biggest football clubs have made it a priority to promote and fund their academy systems on the basis that as well as producing a steady stream of readily available young talent, they also have the potential to make plenty of money in transfers.
The CIES Football Observatory has been examining which clubs are faring best when it comes to their youth production lines and has produced a top 50 of the teams to have generated the most income from their academies since July 2015.
The data takes into account income generated directly from the transfers of players who have spent at least three years in a given club's academy between their 15th and 21st birthdays.
Portuguese giants Benfica are top of the list having made an astounding €379 million in profit from the transfers of their academy graduates over the past seven years, but there are plenty of other big names tucked just behind them in the upper reaches of the table.
Here are some of the main takeaways from the CIES report, which you can see in full here.
Benfica the big winners
According to CIES, Benfica can boast having the most "profitable" academy by some margin, having made €379m in transfer income on graduate players since 2015. An impressive 32% of Benfica's total figure was generated by just one player, Joao Felix's €126m move to Atletico Madrid in July 2019 which remains the fourth biggest transfer of all-time. The next Portuguese club on the list is Sporting Lisbon, who are ninth on the CIES list with an academy yield of €209m.
Real Madrid made most among Europe's elite
Real Madrid are running the second most profitable youth system in world football by recouping €330m, according to CIES. The player responsible for the highest percentage of Madrid's total since 2015 is Alvaro Morata who, oddly, has been transferred by the club twice: once when Juventus signed him for €20m in 2014 and, after Madrid triggered a clause to re-sign him two years later, in 2017 when he signed for Chelsea in a deal worth an initial €60m.
Monaco make up top three
The AS Monaco that won the Ligue 1 title and made a thrilling run to the semifinals of the Champions League in 2016-17 was predictably broken up as rising stars like Bernardo Silva, Fabinho, Thomas Lemar and Tiemoue Bakayoko all moved on to top clubs for big fees. But it was Les Monegasques' own youth product, striker Kylian Mbappe, who has gone on to make the biggest splash in world football. No surprise, then, that his €180m move to Paris Saint-Germain in 2018, the second-biggest transfer fee of all time, accounts for a whopping 63% of Monaco's profits from their academy since 2015. Monaco's domestic rivals, Lyon, are fifth on the list.
But when it comes to single players who have generated the highest individual proportion of their former academy's economic success on the CIES list, not even Mbappe can top Jack Grealish. The England international's British-record transfer from Aston Villa to Manchester City last summer for €117m (£100m) equates to 89% of the total funds generated by Villa's youth academy (€132m), placing Villa 23rd on the list. The only other player who comes close to Grealish are Christian Pulisic, who generated 79% of Borussia Dortmund's academy income with his €64m transfer to Chelsea in 2019.
Chelsea and Liverpool fly the flag for Premier League
Chelsea and Liverpool are the only English teams in the top 10 of the list. Reigning European champions Chelsea are well known for their youth system which produces many players who spend more time out on loan than in their own club's first-team squad. However, many still go on to have respectable careers elsewhere, and the academy has generated €210m of transfer income for the club since 2015. Liverpool are the only club in the top 10 not to have cracked the €200m mark, with €171m produced by their youth graduates in the same time frame.
Chelsea's biggest fee received came via Tammy Abraham's recent €40m switch to AS Roma, while Liverpool's most lucrative academy windfall was produced by Raheem Sterling's big €59m (£49m) move to Manchester City in the summer of 2015. City are the next highest Premier League side on the list in 17th having produced €145m in transfer income, the highest percentage of which was generated by Kelechi Iheanacho's €30m (£25m) move to Leicester City in 2017.
South American sides
The CIES data takes into account every top-flight club in the world and, while European teams certainly dominate, there is a smattering of clubs from further afield occupying places inside the top 50. Indeed, the three highest ranked non-European side are Flamengo of Brazil (13th, largely thanks to Vinicius Junior's €45m transfer to Real Madrid), River Plate of Argentina (27th) and Santos of Brazil (28th).
English clubs rule the roost
Grouped together nationally, English clubs generated an astounding €2.03 billion from the transfer of academy graduates since July 2015 -- more than any other country. French clubs are second (€1.61bn) while Spanish clubs come in third (€1.39bn) ahead of Italian clubs (€1.11bn) in fourth. Brazilian clubs are fifth overall, having generated more money from selling their youth prospects (€951m) than clubs in Germany (€916m), who are ranked sixth collectively.
Despite having two clubs in the top 10, Portuguese clubs can collectively only hold down seventh spot with a combined tally of €788m, narrowly ahead of their Dutch (€709m) and Argentine (€566m) counterparts.