We all know Warren Buffett, Mark Zuckerberg, Bill Gates, Elon Musk, and Jeff Bezos. Other billionaires, though, are less well known and even secretive. Despite their business exploits and the famous brands that made them rich, many of these icons try to avoid the limelight. Most will know the 10 companies and famous products below, but many people have never heard of the ultra-billionaires behind them.

John, Jacqueline, and Forrest (Jr.) Mars ($76.8 billion). The three siblings--grandchildren of founder Frank Mars--serve on the board of directors of Mars. This iconic brand includes world-recognized chocolates such as Snickers bars and M&Ms. Referred to as a "fortress of silence" and compared to the CIA, Mars continues to keep most dealings close to the vest, and the siblings relish privacy, with the brothers avoiding public photos.

Amancio Ortega ($73.3 billion). The founder of Inditex, Ortega is the world's second-wealthiest person. He obtained much of his wealth from Zara, which he started in 1975. He has since grown the clothing company into one of the largest fashion retailers in the world. He keeps such a low profile that despite being born in 1936, it wasn't until 1999 that the first photograph of him was published. It is believed that he has granted only three interviews ever to journalists.

Bernard Arnault ($40.4 billion). As the CEO of Moet Hennessy Louis Vuitton (LVMH), he leads one of the largest luxury companies in the world. LVMH includes 70 brands, including notable labels such as Christian Dior, Dom Perignon, and Bulgari. While well known is France, he has significantly less name recognition in the U.S.

Jorge Paulo Lemann ($24.8 billion). As a co-founder of 3G Capital, Lemann has acquired an interest in a trove of instantly recognizable brands, including Budweiser, Burger King, and Heinz. The five-time Brazilian national tennis champion is largely unknown in the U.S. Despite often remaining behind the scenes, his business exploits and bold moves are legendary.

Stephan Persson ($23.7 billion). Sweden's richest person, Persson is chairman of the clothing chain H&M. He ran the company, which his father founded, from 1982 until 1998. His son is the current CEO. Persson has many large properties throughout the world, but he continues to live in his native Sweden and largely remain out of the spotlight.

Maria Franca Fissolo ($23.3 billion). Fissolo is the widow of Michele Ferrero, who passed away earlier this year. He led the Ferrero Group, which is perhaps most famous for Nutella and Tic Tac. Like her husband, who avoided interviews and prized secrecy, she avoids being in the limelight.

Alain and Gerard Wertheimer ($20 billion). The brothers, who own the French luxury brand Chanel, keep a low profile in an industry that is dominated by outsize personalities. They keep their personal and financial profiles so low that at one point, industry observers underestimated their wealth by nearly $10 billion.

Dietrich Mateschitz ($11.5 billion). For millions of people looking for a burst of energy, Mateschitz's Red Bull is the answer. Described as one of the successful entrepreneurs of our generation, Mateschitz created a whole new category for energy drinks when he released Red Bull in 1987. Though he has a flair for adventure, he keeps an exceedingly low profile and has even been described as reclusive.

Johann Rupert ($7.1 billion). Most have not heard of Compagnie Financière Richemont, but the company counts well-known brands such as Cartier and Montblanc as part of its portfolio. More headlines go to Rupert's fellow South African countryman Elon Musk, but Rupert is the most powerful businessman there, and has recently used his platform to raise concern about income inequality.

Les Wexner ($7 billion). If you're looking for something sexy to wear (or give), odds are that at some point your attire has been influenced by Wexner. He has been the driving force behind famous brands including Victoria's Secret, Express, and Abercrombie & Fitch. He is presently the longest-serving Fortune 500 CEO. He is well known in his home state of Ohio but remains low key. For instance, his office is across the street from a garbage dump, he rarely speaks to the press, and he keeps many aspects of his life private, including not allowing interior photos of his 315-foot yacht.

Wealth estimates based on Forbes listing as of August 8, 2015