Jack Ma, Alibaba founder and CEO, is seen in China after a long absence.

Alibaba founder Jack Ma, who has been seen in public for the past three years, has started at a school in Hangzhou, according to reports.

The 58-year-old has kept a low profile since criticizing China’s financial authorities in 2020. Mr. Ma is the most prominent Chinese billionaire to disappear amid a crackdown on tech entrepreneurs.

He recently returned to China after more than a year abroad, according to the South China Morning Post. Alibaba’s press release said he spent a short time in Hong Kong, where he met friends and briefly attended Art Basel, an international art fair.

He said Mr. Ma had traveled to various countries to study agricultural technology but did not say why he had gone public in recent years. Mr. Ma, a former English teacher, met staff and toured classrooms at Yungu School in Hangzhou, the city where Alibaba is headquartered.