The football transfer market has long been a place where clubs target young talent, betting on their future potential rather than established reputations. This approach has proven successful in many cases, with clubs securing talented players early before their price tags skyrocket. Expensive U21 signings have become more common in recent years, as clubs seek to identify the next big star. But with these moves, there’s always an element of risk involved.

Let’s take a closer look at some of the biggest moves for players under the age of 21 and see which ones paid off.

1. Kylian Mbappé

Instagram | k.mbappe | Mbappé's record-breaking €210.6 million move to PSG has been justified by his incredible performances.

Kylian Mbappé’s transfer from Monaco to Paris Saint-Germain in 2017 for a reported €180 million, adjusted for inflation to €210.6 million, remains the most expensive U21 signing of all time. Despite this hefty price tag, the forward has more than lived up to expectations.

His incredible speed, skill, and composure in front of goal have made him one of the best players in the world, and his rise to stardom at PSG solidified the club’s financial investment. With his continued growth and success, Mbappé has certainly justified his high transfer fee.

2. Ousmane Dembélé

In 2017, Barcelona made a splash by signing Ousmane Dembélé from Borussia Dortmund for €145 million (adjusted to €169.7 million). However, Dembélé’s time at the Catalan club has been marred by injuries and inconsistency.

While his skill set was undeniable, he never truly lived up to the sky-high expectations placed on him. Barcelona eventually sold him to Paris Saint-Germain for a fraction of the initial fee, leaving many to consider this deal a bust for the Spanish club.

3. João Félix

João Félix’s €127.2 million (adjusted to €144 million) move from Benfica to Atletico Madrid in 2019 was one of the most talked-about transfers at the time. However, Félix struggled to meet the high expectations placed on him. Despite flashes of brilliance, he failed to become the transformative player Atletico had hoped for. After a series of loan moves, his future in top-tier football remains uncertain. His transfer, which once seemed full of promise, ultimately turned into a disappointment.

4. Matthijs de Ligt

When Ajax defender Matthijs de Ligt moved to Juventus in 2019 for €85.5 million (adjusted to €96.8 million), many saw it as a sound investment. While his transition to Serie A was challenging, de Ligt grew into a dependable presence in Juventus’ defense.

After a few years, the club recouped a significant portion of the initial fee by selling him to Bayern Munich. In the end, de Ligt’s transfer can be considered a success, as he contributed solidly during his time at Juventus.

5. Raheem Sterling

Raheem Sterling’s transfer from Liverpool to Manchester City in 2015 for €63.7 million (adjusted to €76 million) has proven to be one of the most successful investments in recent memory. Under Pep Guardiola, Sterling became one of the key players in City’s dominance of the Premier League, contributing with goals and assists. Although his departure to Chelsea in 2022 was a big move, Sterling’s success at City ensures his transfer is viewed as a win for the club.

6. Christian Pulisic

Christian Pulisic’s €64 million (adjusted to €72.4 million) move from Borussia Dortmund to Chelsea in 2019 initially looked like a bright prospect for the American winger. However, injuries and inconsistent form limited his impact at Stamford Bridge, and he struggled to secure a regular starting spot.

In 2023, Pulisic made the move to AC Milan for a significantly lower fee. Despite a promising start to his career, the move to Chelsea didn’t deliver the expected results.

7. Anthony Martial

Anthony Martial’s €60 million (adjusted to €71.6 million) transfer from AS Monaco to Manchester United in 2015 raised many eyebrows. While Martial showcased glimpses of his potential, his inconsistency on the field meant he never truly established himself as a key player at United. After nine years at the club, he left as a free agent, with his time at Old Trafford considered a missed opportunity in terms of his transfer value.

8. Leroy Sané

Instagram | leroysan | Sané's initial years at City, marked by impressive performances, justified the significant transfer fee.

Leroy Sané’s €52 million (adjusted to €61.9 million) move from Schalke to Manchester City in 2016 turned out to be a positive investment for City. Although Sané struggled with injuries in later years, his performances during his first few seasons were integral to City’s success, including winning multiple Premier League titles. In the end, Sané’s move to Bayern Munich didn’t diminish the fact that he had met, if not surpassed, expectations at Manchester City.

9. Vinícius Júnior

Vinícius Júnior’s €45 million (adjusted to €52.6 million) transfer from Flamengo to Real Madrid in 2017 didn’t immediately pay off, with the Brazilian winger taking time to adjust to the European game.

However, over the past few seasons, Vinícius has grown into one of Real Madrid’s most crucial players. His skill and maturity on the field have far exceeded expectations, making his transfer one of the best investments in recent football history.

10. Rodrygo

Rodrygo’s €45 million (adjusted to €51.7 million) move from Santos to Real Madrid in 2018 showed promise from the start. While his development took time, the Brazilian winger eventually established himself as a key player in Real Madrid’s forward line. His consistency and growth at one of the world’s top clubs ensure that his transfer can be viewed as a success, similar to that of his teammate Vinícius Júnior.

The Rollercoaster of Expensive U21 Signings

The landscape of expensive U21 signings is filled with both triumphs and failures. Clubs often gamble on young talent, hoping to secure the next big star before their market value explodes. While players like Mbappé and Vinícius Júnior have proven their worth, others, like Dembélé and Félix, have not quite lived up to the hype.

These moves highlight the uncertainty and excitement that come with signing young players. As the football world continues to evolve, the trend of expensive U21 signings is likely to remain, with clubs always on the lookout for the next breakthrough talent.