With 37-year-old Los Angeles Lakers star Lebron James now officially a billionaire, the only active NBA player to do so has now joined 12 other under-40 members of the billionaire club in the United States.

While he has made more than $385 million on the court, and is the Los Angeles Lakers’ highest-paid active player, most of the funds that catapulted him to billionaire status were earned off the court.

Now worth US$1 billion, according to Forbes, the Olympic gold medallist achieved this status through several other ventures including SpringHill Company, Fenway Sports Group, owned properties and Blaze Pizza.

The Forbes 400, or 400 Richest Americans, is a list published, by Forbes magazine, of the wealthiest 400 American citizens who own assets in the US, ranked by net worth.

Here are the other billionaires who are still under 40 years old, according to The Forbes 400 2021 list.

Baiju Bhatt ($2.9 billion)

An American entrepreneur of Indian decent, Baiju Bhatt is the chief creative officer and co-founder of US- based financial services company, Robinhood.

Worth US$2.9 billion, Bhatt, 38, gained his wealth from the stock trading app.

Robert ‘RJ’ Scaringe ($3.4 billion)

Worth US$3.4 billion, RJ Scaringe catapulted to billionaire status with electric vehicles. The 39-year-old, born in Rockledge, Florida, is an engineer, entrepreneur and CEO of the electric vehicle automaker, Rivian.

Fred Ehrsam ($3.5 billion)

Thirty-four-year-old Fred Ehrsam, worth US$3.5 billion, achieved his billionaire status through cryptocurrency exchange.

After parting ways with Coinbase Global six years ago, the entrepreneur held on to six per cent of the company’s stock and later, in 2018, he co-founded Paradigm, an investment firm with stakes in dozens of cryptocurrency.

Scott Duncan (US$6.2 billion)

Inheriting stakes from his father’s pipeline business, Enterprise Products Partners, the 39-year old is worth US$6.2 billion.

One of four siblings to inherit the fortunes of the midstream natural gas and crude oil company, Scott is the youngest.

Ernest Garcia III (US$9.3 billion)

Thirty-nine-year-old Ernest Garcia III, worth US$9.3 billion, is the CEO and co-founder of Carvana. Carvana sells used cars online and allows customers to pick them up from giant vending machines.

Carvana is a a subsidiary of Garcia’s father’s used car dealer DriveTime.

Nathan Blecharczyk (US$10 billion)

One of the co-founders of the American company, Airbnb, the 39-year old Blecharczyk is currently chief strategy officer of Airbnb and chairman of Airbnb China.

Airbnb is an online marketplace for lodging, primarily homestays for vacation rentals, and tourism activities.

Brian Armstrong (US$11.5 bilion)

With cryptocurrency as Armstrong’s source of wealth, the Coinbase CEO has an estimated net worth of US$11.5 billion.

The 39-year-old, who issued a policy on keeping public activism from the workplace, had his 19 per cent stake jump to 11 figures in value when he took the crypto exchange public in a direct listing in April 2021.

Evan Spiegel (US$13.8 billion)

Spiegel gained his wealth from the popular social media app, Snapchat. The co-founder and CEO, who is just a few weeks shy of 32, is worth US$13.8 billion.

Back in 2015, Spiegel was the youngest billionaire in the world.

Lukas Walton (US$17.2 billion)

Worth US$17.2 billion, Walton is grandson of Walmart founder Sam Walton. Walton inherited one-third of his father’s estate after he died in a plane crash back in 2005.

Sam Bankman-Fried (US$22.5 billion)

This 30-year-old Californian gained his wealth from cryptocurrency. Known by his initials, SBF, the entrepreneur and investor is the CEO and founder of FTX.

Moving his company headquarters from Hong Kong to The Bahamas, SBF has a net worth of US$22.5 billion.

Dustin Moskovitz (US$24.1 billion)

Finding success with fellow billionaire Mark Zuckerberg, 38-year-old Moskovitz, co-founder of Facebook, is worth US$24.1 billion. Some of his success also comes from Asana, which he co-founded with Justin Rosenstein, after leaving Facebook back in 2008.

Mark Zuckerberg (US$134.5 billion)

Perhaps the second most well-known billionaire on this list, the 38-year-old is worth US$134.5 billion. Gaining his wealth from co-founding Facebook, now named Meta, Zuckerberg over time has acquired other popular media platforms including Instagram and WhatsApp.