Hong Kong billionaire Li Ka-shing, 90, announced today he is retiring from his companies.

Li said he will officially step down as the chairman of CK Hutchison and CK Asset later this year and will serve as a senior adviser.

He will be succeeded by his elder son Victor Li Tzar Kuoi.

The 89-year-old tycoon made the announcement at a press conference where his four listed companies, CK Hutchison, CK Asset Holdings Ltd., CK Infrastructure Holdings Ltd. and Power Assets Holdings Ltd., released their annual results.

His net worth is $35.4 billion as of today, and is ranked 24th on the list of world's billionaires, according to forbes.com.

Li is one of the richest and most influential tycoons in Asia, with interests in everything from ports and utilities to telecoms.

His companies employ some 310,000 people in more than 50 nations. According to Forbes, his Li Ka Shing Foundation has donated more than $2.6 billion; over 80 percent has gone to Greater China.

In 1950, after learning how to operate a plant, Li founded a plastic manufacturing company in HK with personal savings and funds borrowed from relatives. 

Li started out by supplying HK and the rest of the world with high-quality plastic flowers at low prices in the 1950s.