Football has always been an alluring realm for millionaires, billionaires, mega-rich businesses and affluent individual investors.
The sport grants access to a unique global market and brings with it a certain level of prestige, particularly so when it comes to successful clubs.
Since the turn of the millennium there has been an influx of so-called oil money into the game, with a number of clubs across the world benefitting.
But what exactly is oil money and which clubs are on the receiving end of investment? Goal takes a look at the phenomenon.
Oil money, as the term suggests, is wealth that has been acquired through the petroleum industry.
Typically, this industry is focused on the extraction and refinement of crude oil in order to cultivate products such as gasoline, fuel oil and plastics.
Football clubs that are said to be run on oil money are those which have received investment from businesses involved in the petroleum industry or, more commonly, those which have been bought outright by groups or individuals whose financial clout emanates from their dealings in oil.
A number of clubs across the world benefit from oil money.
"Not only is Gazprom a leader in its field, it also has a long heritage in football," said UEFA spokesperson Guy-Laurent Epstein of the deal renewal. "We look forward to developing our relationship as we enter a new Champions League cycle."
Qatar itself is set to host the 2022 World Cup, so it is perhaps no surprise that the company is also a partner of FIFAs World Cup.
The increased investment of oil money into football has not been without controversy.
As well as those serious issues, the influx of oil money into football has undoubtedly tilted the board in favour of those clubs who are now able to buy the best players in the world and maintain a stranglehold on the competitions in which they compete. While UEFA has introduced Financial Fair Play in a bid to level the playing field, it has been a fraught process.
Furthermore, when iconic institutions such as football clubs, which have long histories and traditions, are transformed into billionaires playthings, it can have the effect of alienating supporters. While some may embrace the wealth and the success which often accompanies it, others lose their connection, and it leads to grassroots campaigns such as Against Modern Football.
As long as the oil industry is entangled in a socio-economic and political web, it is likely that controversy will never be too far away for clubs whose operations are lubricated by its wealth.
Source : Goal.com