The UFC, the world’s premier professional mixed martial arts (MMA) organization, was acquired by WME | IMG, a private company with more than 800 owned, operated and/or commercially represented events in entertainment and sports. WME | IMG was also UFC’s operating partner.

The UFC transaction is subject to customary closing conditions and terms of the transaction were not disclosed, however The Washington Post claims the price was $4 billion, in what may be the biggest sports transaction to date for an organization. The organization was purchased at a fraction of that price in 2000, for $2 million.

“We’ve been fortunate over the years to represent UFC and a number of its remarkable athletes,” said WME | IMG Co-CEOs Ariel Emanuel and Patrick Whitesell. “It’s been exciting to watch the organization’s incredible growth over the last decade under the leadership of the Fertitta brothers, Dana White and their dedicated team. We’re now committed to pursuing new opportunities for UFC and its talented athletes to ensure the sport’s continued growth and success on a global scale.”

Silver Lake Partners and KKR will join WME | IMG as new strategic investors, along with MSD Capital, L.P. and MSD Partners, L.P. which will provide preferred equity financing.

Founded in 1993, UFC is one of the largest and fastest growing sports brands in the world, particularly among millennials. The organization produces more than 40 live events annually and is the largest Pay-Per-View event provider in the world, according to a representative. UFC continues to capitalize on digital distribution platforms via its wholly-owned subscription over-the-top service, FIGHT PASS, delivering exclusive live events, thousands of fights on-demand and original content to fans around the globe.

Lorenzo J. Fertitta, Chairman and CEO, UFC, said “We’re confident that the new ownership team of WME | IMG, with whom we’ve built a strong relationship over the last several years, is committed to accelerating UFC’s global growth. Most importantly, our new owners share the same vision and passion for this organization and its athletes.”

Upon closing, Lorenzo Fertitta will step down from day-to-day operations, but Frank Fertitta III and Lorenzo Fertitta will both retain a passive minority interest in the organization.

Paul, Weiss, Rifkind, Wharton & Garrison LLP, Kirkland & Ellis LLP, Simpson Thacher & Bartlett LLP, and Proskauer Rose LLP served as legal advisors to the buying group and Freshfields served as legal advisor to MSD Capital. Barclays, Credit Suisse Securities (USA) LLC, Deutsche Bank Securities Inc., affiliates of Goldman, Sachs & Co., and KKR Capital Markets LLC (in alphabetical order) are acting as the buyers’ financial advisors and are providing financing for the transaction.

The transaction was led for the sellers by UFC CFO Nakisa Bidarian, with Milbank, Tweed, Hadley & McCloy LLP as legal advisors, and The Raine Group and J.P. Morgan as financial advisors.