On Sunday, Real Madrid will hold a presidential election for the first time since 2006.Renewable energy entrepreneur Enrique Riquelme is going up against Florentino Perez, who has been in the role since 2009.Perez did not need to call this election as he had an active mandate until 2029, but in a remarkable press conference on May 12 he announced the vote, calling on his rivals to “come out of the shadows” and face him.So, how does the election work? Why must candidates prove personal wealth of €187million (£162m; $219m)? And why have Jose Mourinho and Erling Haaland been dragged into it?Allow us to explain.How does the election work?Real Madrid are one of only four Spanish clubs owned by their members (along with Barcelona, Osasuna and Athletic Club), meaning those fans have a say in how their institutions are run.There are very tight rules governing who can stand for election at Madrid — partly due to changes made to the club statutes in September 2012, three years after Perez returned to power, having also served from 2000 to 2006.Only Spanish citizens can run, and candidates must have been club members for 20 years (it used to be 15). The key change was requiring any contender to advance a bank guarantee proving they have personal wealth equivalent to 15 per cent of Madrid’s annual budget.Revenues have grown dramatically under Perez since the rules were introduced. Madrid’s budget for 2012-13 was €518.7m. The budget for this season was €1.25billion — 15 per cent is €187m.Florentino Perez has been in charge since 2009 (Philippe Desmazes/AFP via Getty Images)This is specific to Real Madrid. At Barcelona, president Joan Laporta relies on help from fellow directors to meet a similar requirement.Once Madrid formally call elections, a 10-day period is triggered during which candidates must present their bids. The club’s electoral board have the power to reject a candidacy they decide does not meet requirements and a vote will only take place if two or more candidates are accepted.Madrid statutes also mean that — unlike Barcelona — the current incumbent, in this case Perez, does not need to resign while the process plays out and can sign players to new contracts or hire a new coach.Who can vote? How?According to Madrid’s statutes, members who are “above age, with full legal capacity and who have been registered with the club for at least one uninterrupted year” have the right to vote. They must also be on Madrid’s electoral roll.Those members can vote by post or at Madrid’s training centre on the outskirts of the city, Valdebebas, on Sunday. They have between 9am and 8pm to cast their vote at the centre’s basketball pavilion, where polling stations will be set up.The club have arranged shuttle services for their members from various points in the city as the visit of Pope Leo XIV to the Spanish capital is expected to cause significant transport disruption. On Sunday, he will hold a mass at Plaza de Cibeles, the fountain where Real Madrid usually celebrate their title wins.Although Madrid have not said when the result will be confirmed, the outcome of Barcelona’s presidential election in March was clear by about midnight local time, with voting having closed at 9pm.What should I know about this particular election?As in previous elections at Madrid and Barcelona, some lofty promises have been made by the candidates.Riquelme, the 37-year-old founder of renewable energy company Cox Energy, announced in a Spanish TV interview on Wednesday night that he would sign Haaland from Manchester City if he were made president. He also signed what he said was a legal document committing him to pay “membership fees for all of Madrid’s 100,000 members next season, should I fail to deliver”.Haaland’s camp and City swiftly denied those claims. A joint statement from the player’s father and his agent Rafaela Pimenta on Wednesday read: “All very entertaining but not true. We wish all the best for both candidates in the Madrid elections.” City responded the following morning, with a spokesperson saying “there is no chance of this happening”, denying the existence of a release clause and threatening legal action.Enrique Riquelme’s claims he would sign Erling Haaland were denied by the player’s camp and his club (Pierre-Philippe Marcou/AFP via Getty Images)Riquelme had already announced former Madrid players Raul and Fernando Hierro as his future sporting director and head of youth academy earlier on Wednesday, adding “a player like (City and Spain midfielder) Rodri will play for Real Madrid” were he to be voted in.During that Riquelme interview on Antena 3 show El Hormiguero (The Anthill), Perez’s campaign posted a video teasing Mourinho’s appointment as Madrid’s next coach.On Thursday, it was confirmed, as first reported by The Athletic, that Madrid will have to pay up to €15m to appoint Mourinho from Benfica for a second spell in charge if Perez wins. The value of the Portuguese coach’s release clause had been around €6m but the appointment has been delayed due to Perez facing a challenger.Perez used his own appearance on Spanish TV show Horizonte on Thursday night to claim he would bid at least €150m for a mystery player if he remains in charge, which would break Madrid’s transfer record.When questioned by the presenter, Perez said the target was not at a Premier League club and also appeared to deny it was Bayern Munich’s Michael Olise or Harry Kane. He added: “It’s not Haaland, but it’s a total galactico. First, we have to talk to the club. We are serious, not like them (referring to Riquelme and his team).”Perez famously won the presidency for the first time in 2000 after pledging to sign Luis Figo from Clasico rivals Barcelona — which he did. Three years later, Laporta was voted in for the first time at Barca after announcing he had an agreement to sign David Beckham from Manchester United. Even if that did not materialise and Beckham went to Madrid, it still helped Laporta.Perez won another term at Madrid in 2004 before stepping down two years later. He returned in 2009 and has not faced a rival since, standing unopposed in the past five presidential elections. The most recent vote for the role came in 2006, and was won by Ramon Calderon.Who is expected to win?Despite Riquelme’s promises, most Madrid members will be sceptical of the other commitments coming off, in the short term at least. Adding to that is the sheer strength of Perez’s position. His campaign messaging so far has leaned heavily on the six Champions League titles won since he returned to power unopposed in 2009.It is difficult to make any firm predictions. There have been internal rumblings of dissent among members over Perez’s recent decision-making, especially his still largely unexplained plan to sell some share of the club to an outside investor, so some may decide to vote for a change.The long-serving Perez still appears to be the favourite, but an upset from Riquelme cannot be completely ruled out.