Hong Kong's richest tycoon Li Ka-shing said Friday he is retiring as chairman of the conglomerate CK Hutchison Holdings, effective in May.

With wealth of about US$34.9 billion, Li, 89, once dubbed "superman" for his rags-to-riches story, ranked 23rd in the latest Forbes World's Billionaires list.

"Having been working since I was 12, still being in good physical shape and having a clear head, I feel grateful," Li said

during the company's results announcement.

His elder son Victor will take the helm while Li will remain an adviser to the company.

The Cheung Kong group's businesses span ports, utilities, infrastructure, energy, telecommunications, property and retail. The group switched where it is incorporated to the Cayman Islands from Hong Kong after a major restructuring in 2015, and sold off Hong Kong assets including The Center tower for a record HK$40.2 billion (US$5.15 billion) in November 2017, seen as signs that Li was losing faith in the future of Hong Kong and China.

Li said the notion that the company was divesting its Hong Kong holdings because he was losing faith in China was "laughable. Only those who have little economic knowledge would say such a thing."

Entertaining questions over issues ranging from politics to his love life, Li voiced support for Carrie Lam, the current head of the Hong Kong government, and for the recently approved constitutional amendment abolishing the two-term limit for the Chinese president.

"If I had a vote, I would vote for the amendment that allows President Xi Jinping to work several more terms," Li said. "The country, in terms of fighting corruption, has progressed a lot. This is a fact."