Silent Treatment

The billionaire siblings are the latest beneficiaries of a booming market for luxury products that has lifted the S&P Global Luxury Index by 24 percent this year.

The surge has exposed at least nine hidden billionaires, including Marina and Alberto Prada Bianchi, the older siblings of Miuccia Prada; Brunello Cucinelli, founder of publicly traded Brunello Cucinelli SpA; U.S. designer Tory Burch, and her ex- husband Chris Burch; and Dolce & Gabbana founders, Domenico Dolce and Stefano Gabbana.

The brothers have guided the family business for 39 years and are the third generation to run the more-than-a-century-old company, which was almost lost to the Nazis in World War II, and has grown into one of the most recognized luxury goods companies in the world.

The calculation gives each brother a net worth of $9.6 billion, and ranks them 120th and 121st on the Bloomberg Billionaires Index.

“They don’t publish their numbers, they don’t publish their figures and they don’t talk about it,” Thomas said. “It’s smart business. They can have lean seasons, even lean years and nobody knows. They play the long game, which they do very well.”

Top End

Sales rose 26 percent in 2011, according to the filing, the best growth rate among its five peers for that year. The label has positioned itself in the top-end of the luxury segment, with a winter line-up that includes $5,000 dresses and $4,000 quilted handbags. Perfume and cosmetics sales -- especially the iconic No. 5 scent -- remain Chanel’s biggest business, and probably represent around 55 percent of its revenue, according to David Wu, a luxury goods analyst at Telsey Advisory Group in New York.

“Chanel No.5 remains one of the company’s flagship products and continues to capture a leading share position in the overall fragrance market,” Wu said. “It’s one of the huge money makers at Chanel.”

The company had an Ebitda margin of 24 percent in 2011, beating L’Oreal’s 19 percent, Estee Lauder’s 17 percent and Kering’s 23 percent. LVMH’s margin was 26 percent and Prada was the top performer with 29 percent.