NEW YORK - HONG Kong tycoon Li Ka-shing has invested US$60 million (S$87 million) in fast-growing social network Facebook, with an option for an additional US$60 million, the All Things Digital blog reported.

Citing sources with knowledge of the deal, All Things Digital said Mr Li is making the investment through a separate entity from the companies he controls, which include Cheung Kong Holdings and Hutchison Whampoa.

The investment follows Microsoft's deal last month to take a 1.6 per cent stake in privately held Facebook for US$240 million, valuing at US$15 billion a company that lets users keep track of their friends online.

Facebook has also sought investments from hedge funds and private equity as it expands operations and builds out a network for advertisers, but blog and media speculation that additional financing was in the works have so far appeared premature.

Mr Li's interest in Facebook could translate into closer ties between the social network and Chinese media services company Tom Group, which the billionaire also backs, according to All Things Digital on Friday.

Representatives from the Li Ka-shing Foundation, Hutchison Whampoa and Tom Group declined comment. Facebook officials were not immediately available.

All Things Digital is owned by Wall Street Journal publisher Dow Jones. -- REUTERS