Until now, OWN had been a 50-50 joint venture between the television star and the cable programming giant. The deal, announced Monday, increases Discovery's ownership stake in the basic cable channel by an additional 24.5% to nearly 75%.
The transaction marks the first time that Winfrey has taken money out of the venture. The channel launched in 2011.
Winfrey, however, will continue to serve as chief executive of the network. As part of the deal, she will work exclusively for OWN in the basic cable space through 2025.
Winfrey, who built her company Harpo Inc. into a juggernaut through her syndicated daytime talk show that ran more than two decades until May 2011, now appears as a special correspondent on CBS' "60 Minutes."
"Creating OWN and seeing it flourish, supported by Discovery and a rapidly growing group of the finest storytellers in film and television, is one of my proudest achievements," Winfrey said in a statement. "I'm thrilled with the network's success and excited about this next chapter in our partnership."
Despite early ratings struggles and staff turnover, OWN has become the top-rated network for African American women with such popular series as “Queen Sugar” and “Greenleaf.” The network has benefited from its relationship with prolific producer
Discovery, based in Silver Spring, Md., also owns the Discovery Channel, Animal Planet and TLC. With a majority stake in OWN, which is available in 80 million homes in the U.S., Discovery can exert more control and consolidate the channel's revenue and earnings on its balance sheet.
"This transaction allows Discovery and Oprah to unlock more value from our partnership; extends once more her commitment to the network; and lets us continue our strong work together to nourish OWN viewers with the content they love," Discovery Chief Executive David Zaslav said in a statement.
Discovery is in the process of acquiring Scripps Network Interactive, which owns such female-skewing channels as HGTV and Food Network. The company's stock is down about 25% this year as Wall Street has soured on cable programming companies, which are most vulnerable to cable cord cutting.
On Monday, shares closed up 7.1% to $20.85.
4:35 p.m.: This article was updated to include additional background on the closing share price for OWN and Discovery.