Verizon today said it has completed its $4.48 billion acquisition of Yahoo's operating business and formed a new subsidiary called "Oath" that includes both Yahoo and AOL.

Oath is "a diverse house of more than 50 media and technology brands that engages more than a billion people around the world," Verizon's announcement said. (Yahoo alone has previously said it already had more than 1 billion monthly users.)

Advertising is key to Verizon's plans for Oath. Since Verizon is a home Internet provider and the largest wireless carrier in the US, its access to Internet subscribers' browsing histories could help boost the Yahoo/AOL advertising business. The Republican-led Congress and President Donald Trump recently wiped out rules that would have made it harder for ISPs to use their customers' browsing history to serve personalized advertising.

Verizon said Oath will "continue to build the industry’s most advanced and open advertising technology solutions, with brands such as One by AOL and BrightRoll that span across mobile, video, search, native and programmatic ads."

Verizon purchased AOL in 2015. Many Yahoo and AOL employees will soon be out of a job, as Verizon is reportedly planning to cut about 2,100 workers from the combined organization, about 15 percent of the total.

Former AOL CEO Tim Armstrong is now the CEO of Oath.

Yahoo CEO Marissa Mayer has resigned from the company. Mayer is set to receive a severance package worth about $23 million and stock compensation worth about $187 million.

"It’s been my great honor and privilege to be a part of this team for the last five years. Together, we have rebuilt, reinvented, strengthened, and modernized our products, our business, and our company," Mayer wrote in a Tumblr blog post.

While Verizon purchased Yahoo's operating business, the rest of Yahoo will be re-named "Altaba." Altaba will essentially be a holding company for the 15-percent stake Yahoo owns in Alibaba, its 35.5-percent ownership stake of Yahoo Japan, as well as patents and some other investments.

Verizon said its "Oath portfolio includes HuffPost, Yahoo Sports, AOL.com, Makers, Tumblr, Build Studios, Yahoo Finance, Yahoo Mail and more, with a mission to build brands people love."

"We have dominating consumer brands in news, sports, finance, tech, and entertainment and lifestyle coupled with our market leading advertising technology platforms," Armstrong said. "Now that the deal is closed, we are excited to set our focus on being the best company for consumer media, and the best partner to our advertising, content and publisher partners."