c.2012 New York Times News Service

c.2012 New York Times News Service

LONDON Renzo Rosso, the Italian executive who has turned cool style into big bucks, is expanding his empire.

On Thursday, Rosso's holding company, Only the Brave, took a controlling interest in Marni, a Milan ready-to-wear brand with a quirky image that was founded in 1994 by the Castiglioni family.

Marni will join other design houses in the OTB group, including the denim giant Diesel, Maison Martin Margiela, Viktor & Rolf and Staff International, the company's manufacturing arm.

''Luxury is a very important market," said Rosso, 57. "I was looking for an iconic brand, and this is a story of an independent company that built a business of 120 million euros with no advertising but a lot of know-how."

Rosso's purchase of a controlling but undisclosed stake in Marni illustrates how Italian companies have realized, rather late in the day, the need to work in groups so they have the financial strength to support growth.

French conglomerates have been quick to add Italian brands to their portfolios. LVMH Moet Hennessy Louis Vuitton took control of Fendi and, more recently, the jewelry and watch maker Bulgari. PPR's brands include Gucci and Bottega Veneta.

''This is an extraordinary opportunity of further development for our company, whilst preserving the brand's identity and the entrepreneurial spirit of our family," said Gianni Castiglioni, chief executive of Marni. His wife, Consuelo, is the firm's creative director, and their two children also work for the company a family arrangement typical for the luxury industry.

But "La Famiglia," however attractive as an image, is no longer enough to support a brand's worldwide development. Marni's offbeat, original style has a strong following in the fashion world, and the brand has more than 100 stores across Asia, Europe and the United States. But Rosso said he thought he could help Marni achieve "new, incredible goals."

The executive, who is seen by the industry as a maverick, with his mop of curly hair and love of motorcycles, brought the consolidated income of his fashion labels to 1.375 billion euros, or $1.8 billion, in 2011 $1.1 billion from Diesel alone.

Through Staff International, Rosso also manages the licenses of international brands including DSquared, Just Cavalli, Marc Jacobs menswear and Vivienne Westwood's Red label. He also made an astute investment in the e-commerce retailer Yoox.