Alibaba Group founder Jack Ma, who helped launch China’s online retailing boom, has stepped down as chairman of the world’s biggest e-commerce company.

The move comes at a time when its fast-changing industry faces uncertainty amid a US-Chinese tariff war.

Mr Ma, one of China’s wealthiest and best-known entrepreneurs, gave up his post on his 55th birthday as part of a succession announced a year ago.

He will stay on as a member of the Alibaba Partnership, a 36-member group with the right to nominate a majority of the company’s board of directors.

Mr Ma, a former English teacher, founded Alibaba in 1999 to connect Chinese exporters to American retailers.

The company has shifted focus to serving China’s growing consumer market and expanded into online banking, entertainment and cloud computing.

Domestic businesses accounted for 66% of its 16.7 billion US dollars (£13.5 billion) in revenue in the quarter ending in June.

Chinese retailing faces uncertainty amid a tariff war that has raised the cost of US imports.

Growth in online sales decelerated to 17.8% in the first half of 2019 amid slowing Chinese economic growth, down from 2018’s full-year rate of 23.9%.

Alibaba says its revenue rose 42% over a year earlier in the quarter ending in June to 16.7 billion US dollars (£13.5 billion) and profit rose 145% to 3.1 billion US dollars (£2.5 billion).

Still, that was off slightly from 2018’s full-year revenue growth of 51%.

The total amount of goods sold across Alibaba’s e-commerce platforms rose 25% last year to 853 billion US dollars (£690 billion). By comparison, the biggest US e-commerce company, Amazon.com, reported total sales of 277 billion US dollars (£224 billion).

Alibaba’s deputy chairman, Joe Tsai, told reporters in May the company is “on the right side” of issues in US-Chinese trade talks.

Mr Tsai said Alibaba stands to benefit from Beijing’s promise to increase imports and a growing consumer market.

Alibaba is one of a group of companies including Tencent Holding, a games and social media giant, search engine Baidu.com and e-commerce rival JD.com that have revolutionised shopping, entertainment and consumer services in China.

Alibaba was founded at a time when few Chinese were online. As internet use spread, the company expanded into consumer-focused retailing and services. Few Chinese used credit cards, so Alibaba created the Alipay online payments system.

Mr Ma, known in Chinese as Ma Yun, appears regularly on television. At an annual Alibaba employee festival in Hanzhou, he has sung pop songs in costumes that have included blond wigs and leather jackets.

He pokes fun at his own appearance, saying his oversize head and angular features make him look like the alien in director Steven Spielberg’s movie E.T. The Extraterrestrial.