Audi AG, the business division of the German luxury brand, announced Wednesday its intention to acquire Ducati, the Italian sportbike manufacturer, from its majority owner, the Investindustrial Group.

The announcement ended a month of speculation dating to a report from the web site of Car, the British automotive magazine, in which unidentified sources told the site’s editors of the purchase plan, reported The New York Times. Terms of the deal were not disclosed Wednesday, but as DealBook wrote, a person briefed on the transaction said the purchase would be made for about 860 million euros, or roughly $1.12 billion.

The Volkswagen Group, which owns Audi as well as low-volume ultraluxury brands like Bentley, Lamborghini and Bugatti, was not mentioned in a media release sent Wednesday by Audi AG. An Audi of America spokesman, Andrew Lipman, would not comment on the reasons that Audi, not its parent, was identified as the buyer, saying only that Ducati and Audi “shared brand values.”

In Car’s initial report, Andrea Bonomi, the Ducati chairman, was said to have called his company “the two-wheel equivalent of Audi.” The VW Group chairman, Ferdinand Piëch, expressed interest in acquiring the sportbike company in 2008, but Investindustrial, a private equity firm, instead expanded its ownership stake.

Ducati was described in Audi’s release by Rupert Stadler, Audi’s chairman, as “one of the world’s most profitable motorcycle manufacturers.” Even so, analysts have questioned the move, saying the company was overvalued and would not offer technologies that could readily find their way into Audi’s engineering, despite Ducati’s experience in wringing big power from compact engines. The purchase does, however, give Mr. Piëch, an avowed motorcycling enthusiast, a toehold in the industry.

At the time the announcement was made, it was not clear how the deal might affect Ducati’s relationship with AMG, the in-house tuning division of Mercedes-Benz. But a statement released Thursday by Daimler, the parent of AMG and Mercedes, noted that the takeover “by a rival car manufacturer has understandably resulted in the end of any further collaboration.” The partnership had consisted primarily of matching color combinations on special-edition vehicles. In the weeks after Car magazine’s initial report, Daimler repeatedly denied interest in buying Ducati.

Founded in 1926 in Bologna, Ducati originally manufactured parts for radios. It also designed cameras during World War II, before building its first motorcycles in 1949.