What is net spend? The difference between a club's expenditure on new players and the income it receives from selling. While some clubs are renowned for keeping the books exceptionally well balanced, like Tottenham Hotspur and Porto, others are somewhat guilty of spending far more than they sell.
Taking statistics from Transfermarkt, here are the 20 teams with the highest net spend in world football from the past 10 years...
20. Aston Villa
Net spend over past decade: £133.02m
Keeping both Everton and Leicester City out of the top 20, Aston Villa's place in this list becomes even more concerning considering they are the only non-top flight club featured. The Villans were a Premier League mainstay and spent big on the likes of Darren Bent and Stewart Downing before they lost their way.
19. Shanghai SIPG
Net spend over past decade: £139.13m
The inclusion of a few Chinese Super League teams here only goes to demonstrate further the financial might of these clubs. The first, Shanghai SIPG, have spent close to £100m on two players alone in the past twelve months, with Brazilian duo Oscar and Hulk arriving to Andres Villas-Boas' side.
18. Guangzhou Evergrande
Net spend over past decade: £139.53m
Similarly to Shanghai SIPG, Guangzhou Evergrande have invested their money in South American talent, with the likes of Jackson Martinez and Paulinho joining manager Luiz Scolari. The Southern China Tigers are extremely successful for all their spending though, having won the last six titles in a row.
Net spend over past decade: £141.56m
The serial spenders in Turkey over the past q0 years, Fenerbahce's net spending correlates with their success in bringing in some big names to Istanbul, such as Robin van Persie and Martin Skrtel. However, their record signing remains the £12m capture of Spanish striker Daniel Guiza from Mallorca back in 2008.
16. Hebei China Fortune
Net spend over past decade: £141.72m
The third and final Chinese Super League team that have significantly outspent what they have earned from sales is Hebei China Fortune. Based in Qinhuangdao, the club now managed by Manuel Pellegrini has invested heavily in foreigners, with Gervinho, Hernanes and Ezequiel Lavezzi among the ranks.
15. AC Milan
Net spend over past decade: £155.75m
Despite multi-million pound deals that saw the likes of Kaka, Thiago Silva and Zlatan Ibrahimovic leave the San Siro, Serie A giants AC Milan sure know how to spend money. I Rossoneri were recently bought by a Chinese consortium and have already splashed the cash this summer, so expect them to rise on this list.
14. Stoke City
Net spend over past decade: £160.66m
The Potters have most certainly established themselves as a Premier League side and judging by these numbers, they are spending like one too. With very few major sales, expensive moves for Giannelli Imbula, Xherdan Shaqiri and Joe Allen have put Stoke City amongst Europe's biggest net spenders.
Net spend over past decade: £169.07m
Spending nearly £400m in the last 10 years, the Black Cats' heavy expenditure has not led to stability and the Wearside club will play in the Championship next season. Hindsight is a wonderful thing and in retrospect, the costly arrivals of Didier Ndong, Jack Rodwell and Steven Fletcher never really came to much.
Net spend over past decade: £176.40
Despite a history of buying gems for cheap, Arsene Wenger has not been afraid to dig deep into the Gunners' pockets in recent years; spending big on the likes of Mesut Ozil, Alexis Sanchez and Granit Xhaka. This hasn't been enough for most Arsenal fans though, who continually call for the Frenchman's exit.
Net spend over past decade: £178.73
Just like their neighbours, Inter are guilty of spending way above what they make in selling players. The San Siro club have paid nearly €700m in player arrivals since 2007, with Joao Mario, Geoffrey Kondogbia and Gabriel Barbosa the latest big money signings to fail to bring I Nerrazurri back to the summit.
Net spend over past decade: £228.60m
Napoli's flamboyant and controversial president Aurelio de Laurentiis is never afraid of using his millions to try and bring the Serie A title to Naples. Despite record signing Gonzalo Higuain's mammoth €90m sale to Juventus, the Naples-based side still manage to prodce a large financial deficit in terms of signings.
Net spend over past decade: £273.99m
Having spent around £850m on players in the last 10 years, Liverpool have been desperately trying to return to their glory days through the acquisition of expensive talent. For every Luis Suarez there was also an Andy Carroll, and now Reds fans will be hoping that new record signing Mohamed Salah will have the same sort of impact as predecessor Sadio Mane.
Net spend over past decade: £274.82m
Only marginally ahead of Liverpool in terms of net spend, Roman Abramovich has not been as willing to splash the cash of late, compared to his first few years in England. Nonetheless, the Blues make the top 10 with ease and recent huge fees for the likes of N'Golo Kante, Micy Batshuayi and Diego Costa maintained Chelsea's reputation as spenders.
Expect to see moves for Juventus' Sandro and Monaco's Bakayoko completed over the next few days...
Net spend over past decade: £311.66m
Since returning to the Serie A following their relegation amidst the Calciopoli scandal, Juvetnus have not been shy in writing out enormous cheques for new players. The aforementioned Gonzalo Higuain is the fourth priciest player in the history of the game, while Paulo Dybala and Miralem Pjanic have also contributed to the giant net spend.
6. Bayern Munich
Net spend over past decade: £342.13m
The dominant team in German football, Bayern Munich illustrate their superiority by spending millions of Euros on new players each summer. To truly exemplify this just take back-up defender Mehdi Benatia, who spent the season on loan at Juventus and is currently the Bavarian side's 10th most expensive signing of all time at £25m.
Net spend over past decade: £451.47m
Taking the net spending up a notch is Barcelona, who, despite possessing a wealth of talent from their academy system, still managed to spend around £850m on transfers since 2007. Both Luis Suarez and Neymar were expensive enough, but even bit-part players like Andre Gomes and Paco Alcacer cost eye-watering amounts at €35m and € 30m respectively.
4. Real Madrid
Net spend over past decade: £469.03m
One of only two clubs to have spent over €1bn on new players in the last 10 years, Los Blancos' active selling policy enables them to remain out of the top three net spenders. Despite record breaking deals for Gareth Bale, Cristiano Ronaldo and Kaka, the 12-time Champions League winners have made good money from Angel di Maria and Mesut Ozil, among others.
3. Paris Saint-Germain
Net spend over past decade: £512.72m
Prior to the Qatari takeover in 2011, PSG were not spending big, but they have made up for that in the last six years. The Ligue 1 heavyweights took little time in breaking the bank, with the likes of Angel di Maria, Edinson Cavani and David Luiz explaining how they've registered over £700m in transfer fees.
2. Manchester United
Net spend over past decade: £520.19m
Manchester United have never been afraid of paying top dollar for talent, but that trend seems to have increased dramatically as a result of Sir Alex Ferguson's retirement. In the last few years alone, the arrivals of Paul Pogba, Angel di Maria, Juan Mata, Luke, Shaw, Eric Bailly and Henrikh Mkhitaryan have taken the Red Devils to second spot in this list.
1. Manchester City
Net spend over past decade: £964.35
No one even comes close to Manchester City, whose net spending exceeds £1bn. Since the Abu Dhabi United Group took over in 2008, the Citizens have shown no boundaries when it comes to making new signings. Kevin De Bruyne, John Stones, Raheem Sterling, Bernardo Silva and Leroy Sane are the club's five most expensive signings, and they all arrived within the two years.