Over the past decade, the transfer market has gone a bit mental. Players cost huge sums of money now and teams are splashing the cash like never before. It's hard to keep up.
To get a better picture, CIES compiled a list of the net spend of every side in Europe's top five leagues since 2012/13, working out which sides have spent biggest compared to how much they have brought in in the transfer market.
Here are the results.
25. Real Madrid (-€179m)
Big-spenders Real Madrid have actually done a great job of bringing a good chunk of money back in.
The €112m departure of Cristiano Ronaldo to Juventus definitely helped their cause, as did the big-money exits of Angel Di Maria, Alvaro Morata, Mesut Ozil and Mateo Kovacic to the Premier League.
With two La Liga titles and four Champions Leagues to show for it, you can't really argue with the results.
24. Leeds United (-€181m)
Leeds don't do a lot of selling, evidenced by the fact that Rio Ferdinand's move to Man Utd in 2002 is still their record sale by a long way.
Chris Wood, Ross McCormack and Jack Clarke are their three biggest departures of the last decade, none of whom broke the £15m mark.
By contrast, their recent return to the Premier League has seen Leeds get brave with their spending, splashing the cash to bring in Rodrigo, Daniel James, Raphinha and Diego Llorente, among others.
23. RB Leipzig (-€186m)
Leipzig are one of the smallest spenders in the top 25. They do buy a lot of players, but none have been more expensive than the €30m spent to bring Naby Keita in from sister side Red Bull Salzburg in 2016.
Their business model of 'buy high, sell higher' has served them pretty well over the years. They nearly doubled their money on Keita and also cashed in on Timo Werner, Dayot Upamecano and Ibrahima Konate for release clauses which actually ended up being well below their true market values.
Leipzig got themselves out of the second tier and are now genuine forces in the Bundesliga.
22. Wolfsburg (-€190m)
Wolfsburg were a little more free-spending than Leipzig, splashing out to sign Julian Draxler (€35m) and Andre Schurrle (€30m), but it's their €20m signing of Kevin De Bruyne which steals the show.
The Belgian ultimately left for Man City for around €76m, breaking the sales record set by Edin Dzeko's own move to City in 2010.
Wolfsburg have been battling to establish themselves as Champions League regulars, but they've been in the competition just twice since 2010, including 2021/22's group-stage exit.
21. Napoli (-€228m)
With an infamous reputation for being tough negotiators, Napoli don't do a lot of sales, but when they can be tempted into selling, the deals are usually huge.
Gonzalo Higuain joined Juventus for €90m in 2016, while Edinson Cavani and Jorginho both brought in €60m fees for their respective moves to PSG and Chelsea.
The Partenopei enjoyed an extended run as the most plausible threat to Juventus' Serie A dominance over the past decade, but they never made it over the final hurdle.
20. Wolves (-€247m)
Another side to have been bitten by the promotion bug, Wolves haven't been scared to spend money since their return to the Premier League, and even before.
Strikers Fabio Silva and Raul Jimenez both set Wolves back around €40m each, while plenty of signings around the €20m mark have been made since they made it to England's top flight in 2018.
The sales haven't been as frequent or high-profile. Diogo Jota's €50m move to Liverpool is on an island of its own at the top of the exit charts, with the €20m sale of Helder Costa to Leeds a not-so-close second.
19. Brighton (-€248m)
Brighton haven't made any massive purchases since their return to the Premier League, but there are a lot of deals around the €25m/€30m mark, including those for Enock Mwepu, Neal Maupay and Adam Webster.
For their return, Brighton have secured a spot as a permanent fixture in the English top flight, and the ambitious Seagulls are looking to build on that over the coming years.
As far as sales go, Ben White's move to Arsenal for around €60m makes up a massive part of their earnings.
18. Leicester City (-€275m)
Having cemented their place in the Premier League, Leicester have been focused on smart signings and launching a quiet assault on the top four.
Youri Tielemans and Wesley Fofana sit at the top of their purchase charts, but both could end up being sold on for profits eventually, with Leicester always ready to cash in at the right price.
For examples of that, you only have to look at Harry Maguire's €87m move to Man Utd or Riyad Mahrez's €68m switch to Man City.
17. Crystal Palace (-€292m)
One of the more surprising teams on this list, Palace's presence is largely down to their inability to sell players for high fees.
Aaron Wan-Bissaka joined Man Utd for €55m, Yannick Bolasie went to Everton for €29m and Alexander Sorloth headed to Leipzig for €20m, but apart from those three, nobody else has brought in over €12m.
Big signings like those of Christian Benteke (€31m) and Mamadou Sakho (€28m) just haven't paid off, but Palace are changing their approach these days and hope to reap the rewards soon.
16. Tottenham (-€336m)
For a team with a reputation for not spending the same kind of money as their domestic rivals, Tottenham are one of just 12 teams to have spent over €1bn in the last decade.
Tanguy Ndombele's €60m signing is still their record, with another nine players arriving for over €30m each. There may not have been any massive signings, but there have been a lot of decent-sized deals.
The exits have been more high-profile. Gareth Bale's €101m move to Real Madrid leads the way, with Kyle Walker's €53m switch to Man City some way behind in second.
15. Newcastle United (-€339m)
After taking longer than most to get bitten by the spending bug, Newcastle have now firmly established themselves as big players in the transfer market.
Bruno Guimaraes and Chris Wood are already two of their top three all-time signings, joining Joelinton at the top of the ranking.
There's a good chance they'll be a litter higher on this list next time it's released...
14. Liverpool (-€347m)
Liverpool definitely spend big, but they've been excellent at topping up their accounts with huge sales.
The Reds have made 12 signings worth in excess of €40m, the leader of which is the €85m spent on Virgil van Dijk. However, that has been balanced out by enormous sales of Philippe Coutinho, Luis Suarez and Raheem Sterling, the three of whom brought in close to €300m on their own.
They're reaping the rewards these days. Jurgen Klopp's men won the Premier League and the Champions League, and they remain among the favourites to win both competitions every year.
13. Bayern Munich (-€363m)
For a club of Bayern Munich's size and success, they don't actually spend like most of their continental rivals do.
The €80m signing of Lucas Hernandez in 2019 came as somewhat of a surprise and is yet to be matched, although Leroy Sane (€60m) and Dayot Upamecano (€42.5m) were substantial recent outlays.
Douglas Costa's €40m sale to Juventus is still the most lucrative in club history, with Bayern not always bothered about making their money back.
12. West Ham United (-€374m)
One of those sides striving to force their way into European competition on a regular basis, West Ham have been spending like a team with those ambitions.
Their two top signings, €50m on Sebastien Haller and €38m on Felipe Anderson, didn't exactly go to plan. That's a common trend with a lot of their biggest dealings, which goes a long way to explaining why the Hammers are yet to take that next step.
Dimitri Payet and Marko Arnautovic are the only players to leave for above €25m in the last decade, but they look set to rake in a pretty penny if they cash in on academy graduate Declan Rice.
11. Inter (-€385m)
Romelu Lukaku is both Inter's record purchase and leading sale. He joined for €74m and left for €113m, with the Nerazzurri good at commanding high fees for their players.
They've used their income, which includes €50m+ sales of Achraf Hakimi and Mauro Icardi, to fund some hefty business in the transfer market. However, most of their biggest purchases of the last decade have struggled to live up to expectations.
Hakimi was an obvious success, but then there's Joao Mario (€40m), Radja Nainggolan (€38m) and Geoffrey Kondogbia (€36m), whose signings Inter fans may be keen to forget.
10. Chelsea (-€413m)
Only two sides have spent more than Chelsea in the past decade, but no team can match their whopping earnings of €1.201bn.
Eden Hazard's blockbuster move to Real Madrid, worth in excess of €115m, played a huge part in that, but Chelsea have cashed in for €60m twice (Diego Costa and Oscar) and have a further eight who brought in over €30m.
Their hectic business has produced plenty of results. In the last decade, they've won the Premier League twice, the Europa League twice and the Champions League once.
9. Aston Villa (-€424m)
Aston Villa have some of the wealthiest owners in English football and have not been afraid to flex that.
Emiliano Buendia (€38m), Ollie Watkins (€34m), Leon Bailey (€32m) and Lucas Digne (€30m) have all come in in the last two years, with three of those signings coming following the €117.5m sale of Jack Grealish to Man City.
Christian Benteke joined Liverpool for €46m in 2015, but Villa's next biggest sale of the past decade was Fabian Delph's €11.5m the same year. The earnings have been limited, to say the least.
8. Everton (-€429m)
Everton have spent like a side with Champions League ambitions over the past decade.
They've thrown big money at Romelu Lukaku and Richarlison, both of which were good deals, but the signings of Gylfi Sigurdsson, Alex Iwobi, Yannick Bolasie, Michael Keane and Moise Kean haven't really impressed.
Everton haven't finished higher than fifth in the Premier League in the last decade and have been tenth of below four times.
7. AC Milan (-€432m)
One of the world's premier sides in the early 2000s, AC Milan have been spending big in an ongoing attempt to reclaim that status. The results, as of yet, have been mixed.
Leonardo Bonucci is their record purchase at €42m, but that's the only deal ahead of the €41m signing of Rui Costa in 2001. Instead, they've bought a boatload of players for around the €30m mark - most of which haven't worked out.
Some well-documented financial issues limited Milan's spending midway through the decade, and they're now focusing on smarter deals instead of bigger ones.
6. Juventus (-€561m)
The powerhouse of Italian football over the past decade, Juventus have a cool eight Serie A titles to show for their massive spend.
The Bianconeri have never been afraid to spend massive sums of money. They paid €117m for Cristiano Ronaldo, €90m for Gonazlo Higuain, €85m for Matthijs de Ligt, €82m for Dusan Vlahovic and €76m for Arthur... and there are plenty of €40m signings to add to the fun.
Their departures have been pretty huge as well, with Paul Pogba's €105m switch to Man Utd leading the way.
5. Arsenal (-€583m)
With just four FA Cup trophies to their name over the past decade, it's safe to say Arsenal haven't really enjoyed value for money when it comes to their €1bn+ spend.
Expensive acquisitions, like the €80m signing of Nicolas Pepe or €64m pick-up of Pierre-Emerick Aubameyang, have brought underwhelming results, and a lot of their top signings read like a who's-who of Premier League disappointments.
Having watched the value of their players diminish, Arsenal have sold just four players for more than €30m in the last decade. Compared to their competition, that's peanuts.
4. Barcelona (-€650m)
You just knew Barcelona would be towards the top of this list.
Their €1.63bn spend is the second-highest over the past decade and involves memorable disappointments like Ousmane Dembele, Philippe Coutinho and Antoine Griezmann - their three biggest signings who cost a combined €395m.
As for departures, Neymar's €222m exit to PSG makes up a big chunk, with Arthur's €76m move to Juventus and Alexis Sanchez's €42.5m Arsenal switch next up in the last ten years.
3. Paris Saint-Germain (-€941m)
Paris Saint-Germain's quest for European dominance has seen them spend huge sums of money without much regard for their earnings from the transfer market.
Any player who they deem capable of helping them to Champions League glory is blocked from leaving, which is why their record sale is still the €40m exit of Goncalo Guedes to Valencia in 2018.
Their focus is solely on incomings. Neymar (€222m), Kylian Mbappe (€145m), Achraf Hakimi (€66.5m), Edinson Cavani (€64.5m) and Angel Di Maria (€63m) are their five biggest signings, and while that spending has created an unparalleled reign of dominance in Ligue 1, it has yet to bring the ultimate goal of European glory.
2. Manchester City (-€984m)
No side can match Man City's €1.699bn spend over the past decade. They've thrown money at all angles in an attempt to build the best squad possible, and they'll see four Premier League titles as a decent reward.
They broke their transfer record to sign Jack Grealish for €117.5m in 2021 but haven't pinched pennies anywhere else. They have eight €60m+ signings, and in the last decade, they've brought in 21 players for above €30m.
Like PSG, City are in no rush to sell anybody who can help them towards their long-awaited Champions League success, with their record sale sitting at the €60m brought in by Leroy Sane.
1. Manchester United (-€1.075bn)
If you're going to be top of this list, you better have enough trophies to justify that. Unfortunately for Manchester United, that just isn't the case. They won the 2012/13 Premier League and 2015/16 FA Cup as well as the League Cup and Europa League in 2016/17.
Is that enough for the side with the biggest net spend in Europe over the past decade? Not even close.
Paul Pogba (€105m), Harry Maguire (€87m), Jadon Sancho (€85m), Romelu Lukaku (€85m) and Angel Di Maria (€75m) are their biggest signings, while United have been prolific with €40m transfers. The results, however, just haven't been there.