ESPN sports business reporter Darren Rovell reveals more details about the UFC's owners, who are in talks to sell the company with bid books being supplied to prospective buyers. (1:04)

The owners of the UFC are in advanced talks to sell the business, sources told ESPN.com.

At least four bidders are believed to have submitted bids for the organization, including WME/IMG, China Media Capital, The Blackstone Group and Dalian Wanda Group. The winning bid, should things proceed, is expected to be for a valuation between $3.5 billion and $4 billion, multiple sources with knowledge of the negotiations told ESPN.com.

UFC president Dana White said reports of the promotion being on the market are not true, telling the Las Vegas Review-Journal that "the UFC is not for sale." On Wednesday morning, White reiterated that stance.

"Yeah, we're not up for sale," White said on "The Dan Patrick Show." "We're always working on deals and our expansion globally. I've been saying since this thing came out: No, we're not for sale. But let me tell you what: If somebody shows up with $4 billion, we can talk. We can definitely talk."

White added: "Obviously, if I'm in the middle of a deal right now, there's a lot of confidentiality involved in it. We're working on expanding. We're working on growing the company and moving it to other territories like China, Japan and Korea. So yeah, we're always working on deals."

Said Dave Sholler, UFC's vice president of public relations and athlete marketing: "As a private company, we don't discuss speculation or rumors related to our business."

Lorenzo Fertitta, left, and Dana White are both part of UFC's group of owners. Chance Yeh/WireImage

ESPN contacted those said to be interested in the sale. Representatives of WME/IMG and the two Chinese companies, Wanda and CMC, could not be reached immediately. A representative with Blackstone said the company is not considering a bid.

On Wednesday, sources with knowledge of the potential sale told ESPN that the bid book, prepared by boutique investment bank The Raine Group on behalf of UFC owners Zuffa LLC, was sent to prospective bidders in late March. New information was still being shared with prospective bidders this week, one source with knowledge of the negotiations said.

The Raine Group has advised the UFC in the past, and it also has relationships with two of the bidders. WME/IMG was a founding investor in the investment bank, and The Raine Group formed a strategic partnership with China Media Capital in 2013.

Investment bank Goldman Sachs has also been representing Zuffa, which bought the UFC in 2001 for only $2 million. Sources with knowledge of the numbers presented to potential investors represent UFC's last full-year earnings in the $200 million to $250 million range, before interest, taxes, depreciation and amortization. Investors were advised that a new television rights deal, which would begin in 2019, could add an additional $250 million in annual revenue to the bottom line.

Lorenzo Fertitta, who with his brother Frank owned more than 80 percent of the business at last public acknowledgment, told CNN in December that the private company grossed about $600 million in revenue last year. Besides the Fertittas, who are each worth about $1.6 billion, according to Forbes, the company has two other minority investors: White and the Abu Dhabi government, which, under its Flash Entertainment arm, bought a 10 percent stake in the business for an undisclosed sum in 2010.

The leader in the bid to buy the biggest mixed martial arts business in the world is said to be Chinese-based conglomerate Dalian Wanda Group, sources said. Its chairman, Wang Jianlin, is the richest man in China, worth nearly $35 billion, according to Forbes Magazine.

The company has slowly been integrating itself into sports. Last year, Wanda bought a 20 percent stake in soccer superpower Atletico Madrid for a reported $48 million. In March, amid the FIFA scandal, the company agreed to sign on as a FIFA partner, the highest level of sponsorship, through 2030.

In January, Dalian Wanda Group became the first Chinese company to become owners of a major Hollywood film studio; the group agreed to buy Legendary Entertainment from Pittsburgh Steelers minority owner Thomas Tull for about $3.5 billion.

The UFC, under parent company Zuffa, is privately owned and does not publicly reveal financial information. It's safe to say, however, the company is coming off a monster financial year in 2015, led by the emergence of crossover stars in Ronda Rousey and Conor McGregor.

Rousey and McGregor each headlined three UFC events in 2015. Rousey's title fight against Holly Holm in November set a new company attendance record at Etihad Stadium. One month later, McGregor's title fight against Jose Aldo in Las Vegas drew the promotion's second-highest gate receipts in its history, with ticket sales grossing more than $10 million.

Other bidders said to be in the mix are WME/IMG, which owns media properties and represents athletes, including Rousey, the former UFC bantamweight champion. Blackstone Group is also believed to be a bidder. A senior executive at the private equity firm, David Blitzer, owns a minority stake in the New Jersey Devils, Philadelphia 76ers and British soccer team Crystal Palace.

Another bidder is state-backed investment firm China Media Capital, which in October beat out Dalian Wanda and national broadcaster CCTV to win the broadcast rights for the Chinese Super League, the highest level of soccer in the country. In December, CMC, with another Chinese investment group, Citic Capital, bought a 13 percent stake of British soccer team Manchester City for a reported $400 million. UFC executive vice president Garry Cook was CEO of Manchester City from 2008 to 2011.

It's not surprising that the leading bid is said to be from China. Chinese companies have made $110.8 billion worth of deals in 2016 compared with $106 billion for all of 2015, according to Dealogic, a financial markets data provider.

ESPN.com MMA staff writer Brett Okamoto contributed to this story.