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 22 years old, with the tenth youngest being 31 years old. Earlier this year there were reports that 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 has an estimated net worth of $900 million and turned 21 in August 2018.

According to Forbes' 2018 World Billionaires rankings, there were 63 billionaires under the age of 40 with a cumulative wealth of $265 billion. This group is roughly 3% of the total number of world billionaires and about the same in terms of cumulative wealth. Here's how the fortunes of the youngest billionaires have fared over the past few iterations of these rankings.

Let's now take a look the list of this year's youngest rich people in the world:

1. Alexandra Andresen

Age: 22 years

Net worth: $1.4B

Born in 1996, Alexandra Andresen is the world's youngest billionaire. 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.

Alexandra and Katharina Andresen

2. Katharina Andresen

Age: 23 years

Net worth: $1.4B

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. 

3. Gustav Magnar Witzoe

Age: 25 years

Net worth: $1.9B

Gustav Magnar Witzoe owns nearly half of SalMar 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. 

4. Evan Spiegel

Age: 28 years

Net worth: $4.1B

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. 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 $4.1 billion.

Evan Spiegel

5. Ludwig Theodor Braun

Age: 28 years

Net worth: $1.7B

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 and is now a major medical instruments firm. His father took over the reins of the company in 1977.

6. John Collison

Age: 28 years

Net worth: $1B

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 Irish entrepreneur devised the idea for Stripe with his brother, Patrick, when they were both attending university in Boston. After a recent round of funding, the company is valued at a whopping $20 billion, according to reports. 

Patrick and John Collison

7. Patrick Collison

Age: 30 years

Net worth: $1B

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.

8. Bobby Murphy

Age: 30 years

Net worth: $4.2B

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. 

9. Wang Han

Age: 30 years

Net worth: $1.2B

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. 

10. Eva Maria Braun-Luedicke

Age: 31 years

Net worth: $2B

Eva Maria Braun-Luedicke own 12% of B. Braun Melsungen. The company manufactures injection solutions and surgical instruments. It had over $7.9 billion in sales for 2017.