No surprises here, as Facebook founder Mark Zuckerberg claims the accolade for the richest American under 40.
Indeed, Zuckerberg's fortune, which is now worth $47.1bn, is more than four times as much as the second person in the ranks – his college pal and Facebook co-founder Dustin Moskovitz, who has a net worth of $9.7bn.
In fact, eight of the top 40 richest individuals under 40 in the US can trace their wealth back to Facebook.
At number three is Jan Koum, who came to America at age 16 and found a flat through government housing, to then go on and found WhatsApp, the world's biggest mobile messaging service with 800m users. It sold to Facebook in 2014 for $22bn in cash and stock. Koum has a net worth $8.8bn.
It probably also won't be that surprising that the list, comprised by Forbes, is dominated by Californian techies. Of the 40 most wealthy under 40, 39 are men, 34 made their money in the tech sector and 33 live in California.
What else have they created? Hold your breath: Uber, AirBnB, Fitbit, GitHub, Instacard, Pinterest, Twitter and Snapchat.
Twitter and Square's Jack Dorsey gets in at number 11 with a net worth of $2.2bn, while Bobby Murphy and Evan Spiegel, Snapchat's founders, are the only two billionaires in their twenties.
Read more: Where are the richest people in the world?
But on the list, some 21 individuals are billionaires, and all 40 have net worths of $400m or more. The only woman in the pack is Elizabeth Holmes, who founded Theranos, a blood test company, at the age of 19. She has a net worth of $4.5bn.
Tiger Woods, meanwhile, became the first athlete to get onto the list, despite losing his world number one status. His net worth is $700m.
And with richest-man-in-the-world Jeff Bezos's fortune at $58.2bn, just ahead of Mexican telecoms tycoon Carlos Slim's $57.2bn, it may not be long until Silicon Valley's finest become some of the world's richest people.