Jack Ma, China's richest man, is stepping down as the chairman of the $460 billion Alibaba Group he founded 20 years ago.

The company, founded by Ma and 17 others in a small apartment in 1999, is now the world's largest e-commerce group.

Ma, who's worth almost $40 billion, is known for his love of extravagant celebrations, including mass employee weddings and music performances.

His farewell party is taking place in an 80,000-seat stadium.

Ma's successor is Alibaba CEO Daniel Zhang, who could face challenges from the US-China trade war and a slowing Chinese e-commerce industry.

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Jack Ma, the flamboyant tech personality and the richest man in China, is leaving his $460 billion Alibaba empire 20 years after founding the company.

Ma is stepping down as the chairman of Alibaba Group on Tuesday, his 55th birthday, as part of a long-planned succession scheme. Alibaba Group is the world's largest e-commerce group, with more than triple Amazon's total reported sales for 2018.

A former English teacher, Ma founded the company with 17 others in a small apartment in 1999. It began as a company that sold Chinese goods around the world but shifted its focus to the domestic Chinese market as the country's economy boomed. It later expanded into online banking, artificial intelligence, and entertainment.

The company's 2014 initial public offering remains the biggest in history, at $25 billion. Ma is worth about $40 billion, according to Bloomberg's Billionaires Index, a net worth higher than anyone else in China and 21st in the world.

Alibaba now employs more than 100,000 people, according to Reuters.

While he is stepping down from a major leadership role, Ma said he would take a position in the Alibaba Partnership, a 38-person body with an indirect role in the governance of the group.

Ma has picked Daniel Zhang, the CEO of Alibaba since 2015, to take over, though Zhang is unlikely to match Ma's famous flamboyance.

Ma starred in a kung fu movie, sang at a music festival, and once performed at a company party while dressed as Michael Jackson.

Ma is also known for the extravagant events he holds for employees during Alibaba's annual Singles Day shopping event, whose sales last year quickly outstripped Amazon's Prime Day. The event has featured performers like Mariah Carey and Cirque du Soleil.

And Ma also hasn't held back for Ali Day, which celebrates employees and their families and has even included Ma officiating a lavish employee mass wedding.

Read more: Inside Alibaba's bizarre mass wedding for employees, which is presided over by Jack Ma

His style is also apparent in his resignation plans, which involve a farewell party at an 80,000-seat stadium in Hangzhou, the city where he founded the company decades ago, Reuters reported.

Earlier this year, Ma presided over a mass wedding of 102 couples. REUTERS/Stringer

Alibaba on Monday shared a video of Ma returning to that apartment, where he recalled telling early employees: "This is the place we're going to work for a year probably. We're going to eat here. We're going to sleep here. We're going to work day and night here.

"And we will probably achieve something. Or probably we'll have to go out looking for jobs together."

He said their goal then was to be among the world's 10 most popular websites and to empower small businesses.

Zhang could face challenges amid the trade war between the US and China and a slowdown in the Chinese e-commerce industry.

Liu Yiming, an analyst at the Chinese tech publishing group 36kr, told Reuters that "if Alibaba wants to find new innovations or trends, this is going to be more difficult than before."

"For Daniel Zhang," Liu said, "this will be a big challenge."