Zhang Yiming’s Beijing-based startup Bytedance owns TikTok, whose kaleidoscopic feeds of 15 to 60-second clips feature everything from hair-dye tutorials to dance routines and jokes about daily life.

Since launching in 2017, TikTok has been downloaded more than 1.5 billion times, according to US-based research agency Sensor Tower. It has huge followings in India, the US, Indonesia and elsewhere.

But its rise has raised security fears and last month two senior US senators called for a government review of the app, saying it could leave users vulnerable to spying by Beijing.

Bytedance, which Zhang founded in 2012, prides itself on using artificial intelligence to personalise newsfeeds according to users’ interests.

The company has had “huge and immediate success” because it pays close attention to its young users, said Bo Ji, assistant dean for the Cheung Kong Graduate School of Business.

“The new generation… want to share their real feelings, whether good or bad. They are more direct and expressive,” he said.