Investment funds were emerging across Europe to service the demand for credit among clubs. Ray Ranson, a former Manchester City defender, had flirted with the business of transfer rights before the scandal involving the oligarchs and West Ham. From an office in Manchester, he was making a new push. “There are hundreds of millions of euros of demand out there” from European clubs, Ranson said. “The banks are shut.”

His company, R2 Asset Management, could not operate in the English Premier League because of the ban that Richard Scudamore had implemented, but there were clubs willing to sell him the transfer rights of players in France, Spain, Denmark and Switzerland.

Other financiers followed suit. In Germany, banker Kai-Volker Langhinrichs raised €1 million to invest in the Bundesliga and hired Hamburg midfielder-turned-scout Harald Spörl to advise on which players to take a bet on. In Paris, Laurent Pichonnier, a partner of Fairplay Capital, sounded out the 20 clubs in the French first division. He said that all but Paris Saint Germain and Monaco were interested in doing business.

These fledgling funds, which were more sophisticated than many of the informal investment groups that operated in football, could trace their roots back to an initiative by Boca Juniors in Buenos Aires. La Boca, or “The Mouth”, is the opening of the Riachuelo River and was the arrival point of many Spanish and Italian immigrants to Argentina. Its brightly painted houses and cobbled streets have since become a tourist draw, and tango dancers and painters come out during the day seeking business. After dark, the barrio is a far edgier place and guidebooks advise tourists against walking its streets. Murals on street walls show Diego Maradona holding his arms aloft in Boca's navy blue and yellow shirt and Marxist revolutionary Ernesto “Che” Guevara staring defiantly out at the rest of the world with a steely gaze. Rising up from the neighbourhood is La Bombonera, the “Chocolate Box” stadium where Boca plays had brought the teenage Maradona from Argentinos Juniors.

Seven years later, in 1982, Maradona fetched a world record fee of about $8 million when Boca Juniors traded him to Barcelona. But like in Brazil, such financial windfalls were unpredictable for teams. Boca did not know when they would next make a big sale to a European club. At the same time, Boca fans demanded success and supremacy against arch rival River Plate. So, Boca's presidents were pressurized into spending above the club's means to assemble the best team possible. To raise cash at short notice, Boca Juniors quietly cut deals to sell the transfer rights of players to businessmen. The opaque transactions would come out into the open when Mauricio Macri was elected president of the club in 1995.

The son of a successful businessman in the construction industry, Macri went to university to study civil engineering and then took a course at New York's Columbia Business School before working for his father and as a credit analyst at Citibank. One Saturday in 1991, Macri was bundled into a van outside his home in Buenos Aires by a gang of three men and driven to a house in the San Cristóbal district of the capital. Macri was held captive in a wooden box in the basement by his kidnappers. Without showing his face, one of the men – who called himself Mario – would come down the stairs with a flashlight each evening and hand him a bag containing a plate of takeout food through a tiny hatch in the box.

As other members of the gang threatened to kill him, Macri tried to create empathy with Mario so that they might take pity on him and spare his life. The two men talked about women and football. The young businessman said that his ambition was to become president of Boca Juniors, although he added “I don't know if I will be able to…well, I don't know if you are going to kill me”. Mario responded with a smile, “how can we kill the future president of Boca?”

After 12 days in captivity, his father paid a $6 million ransom to release his son. On a Thursday night at 9.30 p.m., Mario dumped Macri, still bound and blindfolded, on a patch of wasteland and told him to bite through the rope to free himself. Ten minutes later he stumbled to a main road and hailed a cab to a friend's house and freedom. He would later say that the experience had given him a new determination in life. Macri used his father's contacts to become elected as president of Boca just as Maradona returned from Europe to play for the club at the age of 34.

Maradona's homecoming to Boca was spectacular. As he walked onto the turf at La Bombonera, the ground was engulfed by ticker tape and swirling navy blue and yellow smoke that matched the team's colours. A huge box was wheeled onto the pitch and opened in front of him to reveal his two young daughters dressed in Boca's kit. They held up a sign that said “Gracias Papá” and the 35-year-old Maradona began to weep. He sported a yellow stripe in his curly black hair and must have felt like the most loved man in Argentina, as thousands of fans chanted his name.

Macri's privileged upbringing and conservative views were not an obvious fit with Maradona, who had a tattoo of Ernesto “Che” Guevara on his right arm. The new president had begun to run Boca Juniors more like a business at a time when European clubs such as Manchester United were starting to do the same. He cut payroll costs and built new VIP boxes to create revenue he would use to refurbish the rest of the stadium. At a pre-season meeting that lasted most of the night, Macri told the squad that he was cutting their win bonuses by 50%. The players, used to getting their way, were incensed. They yelled at him. “They were completely lawless,” Macri later recalled.

Borrowing from an Argentine metaphor, Maradona said Macri – who at age 36 was less than two years older than him – had “less tarmac than Venice”, because he was so inexperienced in football. “He's never been in a changing room in his life,” Maradona spat. “Who is he to come and tell me we are going to pay you this much in bonuses.”

At the time, Boca Juniors trailed arch rival River Plate, which plays 10 miles away at the Estadio Monumental. In Macri's first year in charge, River Plate won the Copa Libertadores, South America's top club competition. With no money to spend, Macri needed finance to reduce River's supremacy. He tried a different approach: he went to the stock-market regulator and said he wanted to set up a fund to trade on the stock exchange that would allow the public to finance the signings of Boca Juniors players in return for a share of their future transfer fees.

Macri's idea was that each of the fund's transactions would be made public. As he told the regulator his plans, they appeared anxious about the chaotic world of football coming into their more genteel environment. “You can imagine their faces,” Macri said. “Between fear and terror.” Macri persuaded them by putting up a $20 million bank guarantee.

The fund, La Xeneize Sociedad de Fondos Comunes de Inversion S.A., raised $14 million from some 1,500 investors to allow Macri to hire Martin Palermo, Nolberto Solano, Walter Samuel and Guillermo Barros Schelotto. La Xeneize means Genovese in the dialect of the Italian city of Genoa, where Boca Juniors' founders came from. The fund took stakes of between 48% and 84% in the transfer rights of the players.

There was a temporary hitch. Trading in the fund was suspended in its second year when an opponent of Macri complained that the president had broken Boca Juniors' statutes by taking a stake in the fund himself. Team rules said that the president himself could not profit financially from the club. The lawsuit was dismissed, after Macri pledged to donate any profit to charity.

While Macri was overhauling Boca's business model, Maradona was battling with what his agent Guillermo Coppola called a “daily war” with cocaine addiction. “He has some wins, some draws and some defeats,” Coppola said. He had shown flashes of his old brilliance over two seasons during his Boca comeback, but after a league match against his first club Argentinos Juniors he tested positive for drugs for the third time in his career and – facing a doping ban – he announced his retirement on his 37th birthday.

Meanwhile, Macri's fund was turning into a successful gamble for investors. Solano joined Newcastle for about $2 million, Samuel moved to AS Roma for about $25 million and Palermo transferred to Villarreal in Spain for some $10 million. The transfers helped the fund to post a 32% return over four years through 2001, just as Argentina froze bank accounts amid one of its worst economic crises. Over the same four-year period, the Buenos Aires stock market plunged in value by 55%.

On the field, things were also working out and Macri could not resist revelling in the glory that came with breaking River Plate's dominance. In a two-leg 2000 quarter final, Boca Juniors came back from 2-1 down to score three goals in the last 15 minutes against River Plate and send its fans into delirium. Macri was so delighted that he walked, fully clothed, into the shower to join striker Martín Palermo. Boca Juniors went on to win the Libertadores Cup three times in the next four years.

Maradona remained unimpressed by Macri, who would go on to become Mayor of Buenos Aires and then, in 2015, president of Argentina. As president he appointed the player agent Gustavo Arribas, who worked on transfer deals for the British owner of Deportivo Maldonado, as head of Argentina's intelligence agency. Arribas reportedly ceded his role at the humble Uruguayan club to his own son, Ezequiel.

There would be no government role for Maradona, who remained at the other end of the political spectrum from Macri. He said that it had been his return to Boca – not the $14 million fund – that had lured so many star players. “I should have had a percentage” of the transfer fees of all the players Macri hired and then traded to European clubs for a profit, Maradona said. “I would give it to the Boca fans as a present.”

On Rua Garrett, a cobbled street in the Chiado neighbourhood of Lisbon, a 28-year-old Portuguese banker had been inspired by the fund Macri created. Duarte d'Orey had a similarly privileged upbringing as the Argentine – heir to a shipping fortune, he had quit his job trading currencies and derivatives at Citibank in Lisbon in 1999 to apply his banking expertise to the family business. The fourth generation of a family with German roots, he stood out for his blue eyes and shock of blonde hair. He was aristocratic enough to make glossy society magazines, often on the arm of a glamorous girlfriend.

D'Orey and a group of young bankers set up First Portuguese Group, a fund management firm which raised money to bet on the rights of players at first-division clubs Sporting Clube de Portugal, FC Porto and Boavista. In cramped modern offices on a sloping street, D'Orey and his colleagues made up business cards which said that First Portuguese was regulated by the Bank of Portugal and the financial market regulator. It was an unusual sideline for the family business, which had entered shipping in 1886 to serve Portugal's trade routes with Brazil, Angola and Cape Verde. The company had transported goods to almost every corner of the world for 130 years. Now they were trading in footballers.

Portugal was one of the key entry points for South American players to Europe. Hundreds of Brazilian players left home every year to play abroad, and they could settle in Portugal more easily because they didn't need a visa or have to learn a new language. At the same time, Portugal, despite its small population, had an impressive record of producing top players like Luís Figo, the 2001 world player of the year who had matured at the academy of Sporting Clube de Portugal.

After raising €3 million, D'Orey bought a share of the rights of six Sporting players. Among them was a 17-year-old called Cristiano Ronaldo from the island of Madeira, who was trying to overcome bouts of homesickness in Lisbon. The fund paid some €627,000 for a 35% stake in the young prospect.

Sporting president Antonio Dias da Cunha craved the short-term financing that transfer market investors could bring.

The club was in a perennial battle with Portugal's two other heavyweight clubs, Benfica and Porto. Fans pored over their results and transfer targets in one or more of three sports newspapers that focused almost exclusively on football. As in Argentina, the presidents who ran the clubs on behalf of members had only a four-year term to succeed or face the axe and so were under pressure to achieve instant success.

D'Orey was onto a winner: the fund got €5.25 million of Ronaldo's transfer fee when the teenager was traded to Manchester United a year later – an 737% return on its money. Two other players the fund had invested in, Hugo Viana and Ricardo Quaresma, moved for big fees to Newcastle United and Barcelona, respectively. Overall, the First Portuguese fund increased in value by 85% in its first two years. Over the same period, Lisbon's stock-market index dipped 2%.

Porto was also hungry for cash, and in 2004 agreed to sell stakes in 10 players including Brazil-born midfielder Deco Souza for €6 million to a separate investment fund run by D'Orey. The team, led to the Europa League title the previous year by coach José Mourinho, had racked up €58 million in losses over the previous three seasons. To drum up investors, they held a roadshow at Porto's stadium and hired the club's former star player Paulo Futre as a pitchman.

A few weeks later, Mourinho's team helped Porto to the Champions League title with a 3-0 win against Monaco. With Jorge Mendes brokering the move, the coach was promptly hired by Chelsea's new owner Roman Abramovich and raided his former club for players; the fund's value swelled by 37% in barely four months.

Over five years through to 2004, D'Orey returned an average annual rate of 13% for investors via the Sporting, Porto and Boavista funds. Yet he was already looking for new investments outside football and would soon start winding the funds down, just as Ronaldo's and Mourinho's careers were taking off in London and Manchester.

As the financial crisis descended on Europe, Ray Ranson was among the new generation of hedge fund managers betting on the transfer market. As a teenager, Ranson had played in the 1981 FA Cup Final for Manchester City against Tottenham in an era before income from satellite television swelled the receipts of British football clubs. The match finished 1-1 and went to a replay that stands out for Argentine Ricardo “Ricky” Villa's dribble through the City defence under floodlights at Wembley Stadium; Spurs won 3-2.

Ranson's interest in finance was piqued on the team bus when he travelled to away games in his early 20s. On those journeys he would chat with insurance broker John Wilson, a wealthy fan who accompanied directors and mixed with them in the boardroom. After he moved on to Newcastle United from Manchester City, Ranson kept in touch with Wilson and they began an insurance business.

Since then his various career twists have seen him ally with the late Chelsea chairman Matthew Harding to raise £200 million of insurance-backed finance for British clubs, as well as having stints as owner of football data company Opta and as chairman of Coventry City. Now, Ranson was working on his latest venture from the eighth floor of a modern glass building among Manchester's neo-Gothic spires.

When we were invited to the offices of R2 Asset Management in 2013, we found a sports science graduate in his early 30s working on a computer in a sparsely furnished open-plan office adorned with black-and-white photographs of The Beatles. His expensive-looking black and silver business card said his name was Paul Smith and he was an analyst for the hedge fund.

Smith was not looking at investment products like stocks, bonds and currencies. His eyes were focused on the profile of Luciano Narsingh, a 22-year-old winger born in Amsterdam. Narsingh was coached at the Ajax academy that produced Johan Cruyff, Dennis Bergkamp and Frank Rijkaard, but he did not make it into the first team because at barely 60 kilos he was deemed too fragile. Now playing at rival PSV Eindhoven, he was starting to show that Ajax might have made a mistake in discarding him.

On his computer, Smith pulled up an eight-page file. According to his data, Narsingh was rated fourth of 80 wingers in the Dutch league, with a 69.9% score based on a variety of metrics such as the success rate of his passes and the number that led to a goal. That ranking made the grandson of Indian immigrants a possible investment opportunity for R2 Asset Management.

Using statistics to make decisions wasn't new in the City of London or even in football as Smith sat at his desk in 2013. Sam Allardyce's Bolton Wanderers had been using statistics since at least 1999 to find an edge in the transfer market. In his previous job, Smith was a data analyst at West Ham. What was novel was to use the same information to seek profits from the transfer market.

Ranson aimed to produce a 50% return on investment within two years. In line with many hedge funds, he would get a 2% management fee and 20% of the profits. Looking out of his floor-to-ceiling office window across the Manchester skyline, he pointed at the array of buildings. “The companies that own them can raise cash against their market value,” he said. “That's all football teams are doing with their strongest assets – their players. We are not hunting for a jackpot by unearthing the next star player, we are providing a sophisticated financial service. We are higher up the food chain.”

This type of talk riled European football bosses. Platini in particular was sick and tired of businessmen who were not directly involved in football “taking money out of the game”. As a 17-year-old rookie, Platini was among the players to strike over a move by French club executives to unilaterally determine the length of their contracts. The players won. Five years later, before the opening match of the 1978 World Cup in Argentina, Platini and two older teammates led a protest over what they thought was their pitiful compensation for wearing Adidas boots. In response, the French national team painted over the three white Adidas stripes on their boots before they went out onto the field.

Now Platini was ratcheting up his criticism of the involvement of investment funds in public. Privately, the power of Jorge Mendes and a few other agents also rankled him and his aides. But to his frustration, FIFA was taking a more careful approach and had commissioned a second study of the transfer market by the Centre de Droit et d'Économie du Sport in Limoges, France. The study was taking months, more than 80 people were being interviewed and Platini was fearful that FIFA would end up doing nothing. “What will happen if FIFA does not act with sufficient consistency, energy and courage?” Platini fretted. “What will happen if the resolution, in the end, is neutralized by pressure from some investment funds blinded by the pursuit of profit?”

A few days later, he took matters into his own hands. UEFA's executive agreed to ban the practice within “three or four years” from its competitions, the Champions League and Europa League. That meant the likes of Atlético Madrid, FC Porto, Sporting Clube de Portugal, Besiktas and FC Twente would soon no longer be able to field players whose transfer rights were part owned by investment funds, if they wanted to continue receiving a share in more than $1 billion of UEFA prize money each year. Privately, fund managers scoffed at Platini, saying he didn't understand they were just providing financing agreements for clubs. They were not, they said, interfering with the market and controlling transfers.

Platini's determination to cut back on the rampant commercialism in football was well received by some of his compatriots in the French parliament. On the banks of the River Seine, at the 18th-century Palais Bourbon, Pascal Deguilhem, a 67-year-old deputy who was a former amateur rugby player, laid out his concerns to fellow parliamentarians. “Today, players meet up at the start of the season, change teams in January and go their separate ways at the end of the season,” he said. The idea of a team representing a town had become redundant.

The lawmakers suggested measures – including one by Terra Nova, a Paris-based think-tank – that transfer fees should be scrapped altogether and players be treated like normal employees. Guénhaël Huet, mayor of a village of 8,000 people in the La Manche region of northern France, was most scathing in his speech about investors buying the transfer rights of players. It was as though they were trading in racehorses, he said.

Privately, Platini and other senior UEFA officials toyed with the idea of reforming the transfer market. The last time transfer rules were significantly altered was in 2001, six years after Belgian footballer Jean-Marc Bosman successfully changed the rules that allowed clubs to charge a fee for a player even after his contract had expired.

One morning the postman had dropped a letter into Bosman's postbox at the end of his neatly tended front lawn, next to where his snazzy Porsche Carrera was parked. It was from RFC Liège, the team he played for, and said that it was offering him a new contract that would cut his pay by 75%. Stunned, Bosman looked for a move to another team. He received an offer from Dunkerque, across the border in northern France, but the French club could not agree terms with Liège. Bosman was stuck and he went to court. After a five-year battle, the Belgian player won his case at the European Court of Justice, forcing FIFA to alter its rules. It took years of bartering to agree on a new set of regulations.

The court fight had left Bosman sidelined from football and now, in his 50s, he was jobless and living on benefits in the same suburban house. He had sold the Porsche long ago. He said that none of today's footballers had thought to contact him. “Not one of them has called me to say thank you,” he said.

As transfer fees continued to rise, causing dismay among some observers, Platini's aides at UEFA looked at a new model that would tie fees to parameters like a player's salary and the number of years he had left on his contract. Their aim was to stop the inflation that was so attractive to investment funds. They drew up a proposal that would drastically reduce the biggest fees for the likes of Cristiano Ronaldo, who Real Madrid had signed for £80 million.

Under the UEFA proposal, which was not made public but circulated internally, fees would be linked to a player's salary: one of the sport's biggest names like Ronaldo, who was earning €10 million or more per year, would be traded for a fee of between €14 million and €28 million. A footballer earning a more modest €600,000 per year – a typical wage in English football's second-tier Championship – could only be transferred for between €300,000 and €800,000.

But the calculations, jotted down on a piece of A4 paper, were complicated and would be troublesome to implement. Leading European clubs were worried that an alternative to distributing football's wealth through transfer fees might erode their financial dominance. Imagine if they had to regularly share a cut of their television revenue among dozens of lower-division teams instead. At least with transfer fees, top clubs like Real Madrid, Manchester United and Bayern Munich retained autonomy over their wealth.

Stefan Szymanski, a sports business professor at Michigan University who has co-written a book about football called Soccernomics, said there was a strong case for changing transfer rules because so little of the fees trickled down to clubs in lower leagues. Earning transfer money was like playing the lottery for smaller teams, he said. It was “remarkable” that neither UEFA nor any other football authority had attempted to produce a scientific study on how to maintain competitive balance in the game.

Without making the plans public, UEFA's back-of-the-envelope calculations about altering the regulations did not go any further, apparently because it was too complicated to make any changes. The 125-year-old transfer system may not have been perfectly designed, but it would be highly tricky to overhaul. It was a bit like the London Underground train network, started in 1894. The transport system was in need of an upgrade, but any effort to bring it up-to-date in one sweeping move would cause no end of complaints and disruption. It was far easier to tinker with the existing model.

As one of the game's senior statesmen, Platini had other ways of exerting influence on how the market operated. He controlled the money-spinning Champions League and the European Championship, the national team competition held every four years. The two competitions generated billions of euros in television revenue and sponsorship. Among the businesses angling for a cut of this revenue was CAA, the Beverly Hills-based company that managed an investment fund led by Peter Kenyon, the former Manchester United and Chelsea chief executive.

The fund had acquired stakes in players from Lisbon-based Sporting, among other clubs.

Some of the young footballers at Sporting were represented by Mendes who, according to Kenyon, was to be paid a commission when the fund made money on transfers. Critics said it wasn't right for an agent to act for a player and also have an interest in his transfer rights. FIFA examined Mendes's involvement with the CAA investment fund but did not even question him, let alone take any action, according to a person familiar with the case. Kenyon, speaking from CAA's office in London's Hammersmith, said the fund was “very conscious” that it should not interfere with player trading. “We've been aware of conflict and we've managed that conflict,” Kenyon said. Kenyon said that Mendes's career showed he wasn't interested in a quick profit. “He's developed players in conjunction with their clubs,” Kenyon said. After all, his biggest client, Cristiano Ronaldo, had spent six years at Manchester United.

However, pressure from Platini appeared to pay off. CAA, which had recently won a contract to manage the marketing rights of the 2016 UEFA European Championships in France, said it was disposing of the transfer market fund and it was clear where its priorities now lay: it set up an office a mile away from UEFA's headquarters on the banks of Lake Geneva.