A surge in global demand for luxury goods and clothing has unveiled three Italian billionaires as valuations of the world’s best-known fashion brands soar.

Domenico Dolce, 54, and Stefano Gabbana, 50, the co- founders of Dolce & Gabbana Srl, the Milan-based fashion retailer whose Plumeti Tulle and Lace prom dresses sell for about $4,000, have joined the ranks of the world’s richest, according to the Bloomberg Billionaires Index.

Sandro Veronesi, the 53-year-old owner of closely held Calzedonia Group, the retail franchise that sells bras, bikinis and briefs through its Intimissimi and Tezenis brands, has also amassed a 10-figure fortune.

“They are in two completely different market segments,” Carlo Pambianco, founder of Milan-based fashion consultancy Pambianco, said by phone. “Both are among the most valuable unquoted fashion companies in Italy.”

Growing global consuming spending has fueled a bull market for fashion retail companies. Shares of Italy’s Prada SpA more than doubled in 2012. New York-based Michael Kors Holdings Ltd. shares were up 87.3 percent during the year, and Germany’s Hugo Boss AG rose 44.5 percent.

’Consuming Class’

Fashion billionaires are benefiting from what New York- based consultancy McKinsey & Co. calls the “rise of the consuming class.” According to an October 2012 luxury goods report from Boston-based Bain & Co., global sales of apparel, accessories, cosmetics and fragrances expanded by 10 percent in 2012 to $275 billion, the third straight year sales grew by at least 10 percent.

“There’s solid momentum in the sector driven by strong demand out of the newer markets,” said David Wu, a luxury goods analyst at Telsey Advisory Group in New York. “China continues to be a huge growth opportunity and more attention is being paid to Brazil and India especially.”

At least four other fashion billionaires have been created in the past 12 months, according to data compiled by Bloomberg. None have appeared on an international wealth ranking.

Among them: Spain’s Sandra Ortega-Mera, the 44-year-old daughter of Amancio Ortega, the founder of the Zara chain and the world’s third-richest man; Tory Burch, 46, the co-founder of New York-based shoe and handbag-maker Tory Burch LLC; and Prada executives Marina Prada and Alberto Prada Bianchi.

Arnault, Pinault

Dolce & Gabbana is valued at $5.3 billion, according to data compiled by Bloomberg, applying the 1.1 billion euros ($1.5 billion) revenue in 2011 as reported by the company to the average enterprise value-to-earnings before interest, tax, depreciation and amortization and price-to-earnings multiples of four publicly traded peers: London-based Burberry Group Plc, New York’s Ralph Lauren Corp., Prada and Hugo Boss. Enterprise value is defined as market capitalization plus total debt minus cash.

Dolce, who is D&G’s chairman, owns a 41.8 percent stake in the company, filings with the Italian Chamber of Commerce show, giving him a net worth of at least $2.2 billion. Gabbana, who is president, controls a 40 percent stake valued at $2.1 billion.

The remainder of the company is held by Dolce’s siblings, Alfonso and Dorotea, according to Orbis, a database of company information published by Bureau van Dijk. Paola Locati, a Dolce & Gabbana spokeswoman, said they declined to comment on the net worth estimates.

“Freedom means not having anything that forces you to do what you don’t want to do,” Dolce said in a 2005 interview with Time magazine explaining their persistent refusal to sell out to suitors including Bernard Arnault’s LVMH Moet Hennessy Louis Vuitton SA, the world’s largest luxury-goods company, and the Gucci Group, owned by Francois Pinault’s PPR SA.

Milan Nightclub

Dolce and Gabbana met in a Milan nightclub. Their designs first appeared on Milan’s fashion show catwalks in 1985. The billionaires, who were romantically involved for about 20 years, became embroiled in a court battle over charges of tax evasion in 2007.

The designers are accused by Italian prosecutors of selling their clothing brands to their wholly-owned Luxembourg-based holding company, Gado, for less than a third of their market value, each avoiding more than 416 million euros ($540 million) in taxes.

Both have denied the charges. Gabbana threatened to leave the country in a Twitter post last November. Their trial is scheduled to begin Jan. 30.

Such distractions have done little to derail their product line, which is known for edgy designs and luxury pricing, according to Pambianco. Its dresses, leather goods and perfumes are sold at 251 Dolce and Gabbana outlets and other retail stores worldwide.

“They always are provocative in some way or other,” he said. “They are completely different from Armani which is much more restrained.”

Democratic Underwear

Calzedonia’s business model takes the opposite approach, selling low-priced lingerie and swim-wear through a network of 3,200 owned and franchised stores in Europe. Veronesi founded the company in 1986 to sell stockings, before expanding into underwear with Intimissimi in 1996, and Tezenis in 2003.

Veronesi’s 85 percent control of Calzedonia is valued at $1.9 billion, according to the Bloomberg ranking, based on the average enterprise value-to-Ebitda and price-to-earnings multiples of two publicly traded peers: Columbus, Ohio-based Limited Brands Inc., the owner of Victoria’s Secret, and La Senza brands.

Calzedonia declined to comment on Veronesi’s net worth estimate.

Strict Controls

Calzedonia maintains strict controls over its brands and product lines, keeping each focused on targeted consumers. Tezenis focuses on younger consumers, while the Calzedonia chain sells stockings and socks. Veronesi acquired knitwear label Falconeri in 2009, adding jumpers and jackets to the range.

Veronesi has said Calzedonia’s will grow in northern Europe and the Middle East before expanding in Asia and the U.S.

“We focus on Europe, because although we are very strong in Southern and Eastern Europe, we have little presence in the North,” Veronesi told Italian fashion magazine Moda24 last year.