Thanks to family inheritances, family businesses, and technology startups, there seem to be more young billionaires today than at any point in history.  According to Forbes, the youngest billionaire in the world comes in at just 21 years old, with the tenth youngest being 32 years old. Kylie Jenner is on the cusp of being the world's youngest self-made billionaire, a title that Mark Zuckerberg, co-founder and chief executive officer (CEO) of Facebook (FB), earned in 2006 at the age of 23. Jenner, now 20 years old has an estimated net worth of $900 million and will turn 21 in August 2018.

This list is according to Forbes' real-time net worth ranking as of July 11, 2018.

1. Alexandra Andresen

Born in 1996, Alexandra Andresen is the world's youngest billionaire, at just 21 years old. She is a Norwegian heiress and the daughter of Johan H. Andresen Jr., who owns Ferd, a Norwegian investment company that runs hedge funds, actively invests in the Nordic Stock Exchange, and has private equity investments. In 2007, Andresen and her sister, Katharina, were each transferred 42.2% of the ownership stakes and subsequently inherited the money. Andresen has an estimated net worth of $1.4 billion. 

2. Katharina Andresen

Katharina Andresen is the world's second-youngest billionaire, as only her sister Alexandra is younger. Andresen also inherited 42.2% of the Ferd ownership stakes. She is 23 years old and has an estimated net worth of $1.4 billion. 

3. Gustav Magnar Witzoe

Gustav Magnar Witzoe owns nearly half of Salma ASA, one of the world's largest salmon producers. Salmar spearheaded the industrialization of salmon farming in Norway. This stake was given to him in 2013 by his father, Gustav Magar Sr., who founded the company in 1991. Because Witzoe Sr. still runs the company, Gustav invests in real estate and tech startups. He is 25 years old has an estimated net worth of $2.7 billion.

4. John Collison

John Collison is the owner and co-founder of Stripe, a company that builds software for businesses to plug into websites and apps to instantly connect with credit card and banking systems in order to receive payments. The 27-year-old Irish entrepreneur devised the idea for Stripe with his brother, Patrick, when they were both attending university in Boston. The company is valued at $9.2 billion, and Collison himself has an estimated net worth of $1 billion.

5. Evan Spiegel

Evan Spiegel is the co-founder and CEO of Snap Inc, a camera company which operates Snapchat — a photo messaging service that delivers temporary photos between friends. Snap Inc has a market cap of $16.7 billion as of July 11, 2018. Spiegel studied product design at Stanford University, where he met his co-founder and fellow billionaire, Bobby Murphy. Evan Spiegel is 28 years old and has a net worth of $3 billion.

6. Ludwig Theodor Braun

Ludwig Theodor Braun owns 10% of the medical device company B. Braun Melsungen, which was founded in 1839 as a small pharmacy that sold herbal remedies. Now, the company manufactures injection solutions and surgical instruments. The company had over $7.9 billion in sales for 2017. Braun is 28 years old and has an estimated net worth of $1.6 billion.

7. Bobby Murphy

Bobby Murphy is the second half of the co-founding pair that brought Snap Inc to the marketplace, and he also owns the company. Murphy is older than his fellow co-founder Spiegel and studied mathematics and computational science at Stanford University. Murphy is 29 years old and has an estimated net worth of $3 billion.

8. Patrick Collison

Brother of John Collison, Patrick is the co-founder and CEO of Stripe, the company that allows businesses and individuals to easily accept payment over the internet. Stripe's big-name investors include Elon Musk and Peter Thiel. Collison is 29 years old and has an estimated net worth of $1 billion.

9. Wang Han

Wang Han inherited wealth from the shares he holds in Juneyao Air, a major airline company based in Shanghai. He inherited the shares from his deceased father who founded Juneyao Group which also has business involvement in retailing, education, and food. Han is 30 years old and has an estimated net worth of $1.3 billion.

10. Lukas Walton

Lukas Walton is the grandson of the famous founder of Walmart Inc. (WMT), Sam Walton. He inherited his fortune as well as one-third of the family estate from his father, John Walton, who died in a plane crash in 2005. An active investor and philanthropist, Walton owns stakes in Walmart, First Solar, and Arvest Bank. He is 32 years old and has an estimated net worth of $14.2 billion.

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