Adidas sells Reebok to Authentic Brands for $2.5 billion.

Sixteen years after acquiring Reebok for $4 billion, the German sportswear giant Adidas is selling it for a little more than half that to Authentic Brands Group, the voracious acquirer of struggling brands.

In the past few years, Authentic has acquired Brooks Brothers and Forever 21, adding to a stable that includes Sports Illustrated. The acquisition of Reebok for 2.1 billion euros, or $2.5 billion, comes as Authentic is preparing to go public.

“We’ve had our sights set on Reebok for many years,” the chief executive of Authentic, Jamie Salter, said in a statement. “Reebok not only holds a special place in the minds and hearts of consumers around the world, but the brand also has expansive global distribution.”

Reebok operates in 80 countries, with roughly 70 percent of its business outside the United States and Canada. Its world headquarters will remain Boston.

When Adidas acquired Reebok in 2005, it hoped Reebok could recapture the glory of its 1980s heyday and create a formidable rival to Nike. But the brand got lost inside the broader Adidas empire and struggled to connect with consumers. Sales of Reebok fell 19 percent in 2020 to 1.41 billion euros, from 1.75 billion euros the year before.

“For a given period of time, the brand was probably stronger than the products,” Kasper Rorsted, the Adidas chief executive, said of Reebok in 2016. “Right now, I would argue that our products are stronger than the brand, and we need to make sure that we reconnect our consumers with the brand that we have.”

Adidas is no stranger to selling off struggling businesses, deals that have been met with varying degrees of success. Its sale of the golf gear brand TaylorMade proved a win for the buyer, the private equity firm KPS Partners, strengthened in part by its deal with Tiger Woods. (KPS has since sold the brand.) But the shoe brand Rockport, which Adidas sold to Berkshire Partners, filed for bankruptcy, blaming its former parent for a sale process that “took meaningfully longer and was significantly more expensive than planned.”

Shaquille O’Neal, whose shoe line with Reebok was introduced in 1992 and who sold a stake in his own brand to Authentic Brands in 2015, celebrated the sale. “It’s a dream come true to welcome this legendary brand to the family,” he said in the statement from Authentic.

Last year, Mr. O’Neal told CNBC that he was intent on owning Reebok, arguing that Adidas had “diluted” it so much “to where it’s almost gone.”