A billionaire, in countries that use the short scale number naming system, is a person who has a net worth of at least one billion (1,000,000,000) units of a given currency, usually the United States dollar, the euro, or the pound sterling. Forbes magazine updates a complete global list of known U.S. dollar billionaires every year.

According to the Forbes report released in March 2012, there are currently 1,226 U.S. dollar billionaires worldwide, boasting a combined total net worth of $4.6 trillion. The United States is home to 425 billionaires, while Russia and China have 96 and 95 billionaires respectively. Among U.S. billionaires, the average age is 66 years.

In countries that use the long scale number naming system, a billionaire would have one million million (1,000,000,000,000) units of currency. Under the short scale number naming system, an individual with such a fortune would be a trillionaire. There are no known euro or U.S. dollar trillionaires – in U.S. dollars, such a fortune would be roughly equivalent to the entire 2010 gross domestic product of Mexico. However, some individuals have attained fortunes of over one trillion units in other currencies. According to VnExpress, 9 Vietnamese had stock market assets valued at over one trillion đồng (US$47.5 million) by the end of 2011. According to The Korea Herald, there were 16 Koreans with stock market assets valued at over one trillion won (US$895 million) on March 9, 2012. According to the Jakarta Globe, 116 Indonesians had assets worth over one trillion rupiah (US$117 million) in 2011.

Travis Lazarus McCoy (born August 6, 1981), known by his stage name Travie McCoy, is an American singer and rapper. He is the lead vocalist of the alternative hip-hop band Gym Class Heroes. He released his debut solo album Lazarus on June 8, 2010.

Raised in Geneva, New York, McCoy became involved with punk rock scenes as a teenager. He formed the group Gym Class Heroes with childhood friend Matt McGinley, and after several line-up changes, the group was signed to Fueled by Ramen, and released their debut album. The group achieved mainstream success in 2006 when its album As Cruel as School Children was released, Gym Class Heroes are most notable for the song "Cupid's Chokehold".

Gym Class Heroes took a three year hiatus from music, leaving McCoy to focus on his solo career; McCoy released his debut solo album, Lazarus, in 2010. The lead single from the album, "Billionaire" featuring Bruno Mars, peaked at number four on the Billboard Hot 100, and number three on the UK Singles Chart. The single was certified double platinum by the Recording Industry Association of America. McCoy is signed to T-Pain's label Nappy Boy Entertainment.

Peter Gene Hernandez (born October 8, 1985), better known by his stage name Bruno Mars, is an American singer-songwriter and record producer. Raised in Honolulu, Hawaii by a family of musicians, Mars began making music at a young age. He performed in various musical venues in his hometown throughout his childhood. He graduated from high school and then moved to Los Angeles, California to pursue a musical career. Mars produced songs for other artists, joining production team The Smeezingtons.

Mars had an unsuccessful stint with Motown Records, but then signed with Atlantic Records in 2009. He became recognized as a solo artist after lending his vocals and co-writing the hooks for the songs "Nothin' on You" by B.o.B, and "Billionaire" by Travie McCoy. He also co-wrote the hits "Right Round" by Flo Rida featuring Ke$ha, and "Wavin' Flag" by K'naan. In October 2010, he released his debut album, Doo-Wops & Hooligans. Anchored by the worldwide number-one singles "Just the Way You Are" and "Grenade", the album peaked at number three on the Billboard 200. Mars was nominated for seven Grammys at the 53rd Grammy Awards, winning Best Male Pop Vocal Performance for "Just the Way You Are".

Mark Cuban (born July 31, 1958) is an American business magnate. He is the owner of the National Basketball Association's Dallas Mavericks,Landmark Theatres, and Magnolia Pictures, and the chairman of the HDTV cable network HDNet. He is also a "shark" investor on the television series Shark Tank. In 2011, Cuban wrote an e-book, How to Win at the Sport of Business, in which he chronicles his life experiences in business and sports.

Cuban was born in Pittsburgh, Pennsylvania and grew up in the Pittsburgh suburb of Mt. Lebanon, in a Jewish working-class family. His last name was shortened from "Chabenisky" when his Russian grandparents landed on Ellis Island. Cuban's father Norton was an automobile upholsterer. Cuban's first step into the business world occurred at age 12, when he sold garbage bags to pay for a pair of expensive basketball shoes. While in school, he held a variety of jobs, including bartender, disco dancing instructor, and party promoter. He paid for college by collecting and selling stamps, and once gained about $1,100 from starting a chain letter.

Elon Musk (born June 28, 1971) is a South African-born American business magnate, engineer and inventor. He is best known for co-founding SpaceX, Tesla Motors and X.com, which later became Paypal after acquiring the service. He is currently the CEO and Chief Designer of SpaceX, CEO and Product Architect of Tesla Motors and Chairman of SolarCity. While at those companies, Musk co-designed the first viable electric car of the modern era, the Tesla Roadster, a private successor to the Space Shuttle, Falcon 9/Dragon, and the world's largest Internet payment system, PayPal.

Elon Musk was born in Pretoria, South Africa, the son of a Canadian-American mother and a South African father. His maternal grandfather was from Minnesota, and had moved to Saskatchewan, where Musk's mother was born. His father is an engineer and his mother is an author, nutritionist and model, appearing on the cover of New York Magazine in 2011 and a Time Magazine supplement in 2010.

Musk bought his first computer at age 10 and taught himself how to program; by the age of 12 he sold his first commercial software for about $500, a space game called Blastar.