HONG KONG/SINGAPORE (Reuters) -China Mobile, the world's biggest wireless carrier by users, is moving closer to a deal to take over Hong Kong broadband company HKBN ( HKBNF ) after rival bidder I Squared Capital dropped out of the race, three sources said.

U.S.-based global infrastructure investor I Squared was preparing to trump China Mobile's offer of HK$5.23 per HKBN ( HKBNF ) share made in December, but was not keen to pay more than HK$6 apiece, Reuters reported in January.

I Squared however did not secure approval from Chinese sovereign wealth fund China Investment Corp (CIC) to go ahead with the bid for HKBN ( HKBNF ), said the sources, who have knowledge of the matter.

CIC vetoed the deal as a minority shareholder in I Squared-controlled HGC Global Communications in Hong Kong, as a potential acquisition could affect the operations of the fixed-line operator, which also has a broadband business, said one of the sources.

I Squared and CIC declined to comment. State-owned China Mobile did not immediately respond to Reuters' requests for comment.

China Mobile made its takeover offer in early December, valuing HKBN ( HKBNF ) at HK$7.8 billion ($996.1 million), after first showing interest nearly two years ago. The company currently has a market value of HK$7.6 billion with the stock at HK$5.10 on Wednesday.

Deal terms are still being negotiated and could be affected by a mismatch in valuation expectations, one of the sources said. All the sources declined to be named as the matter was confidential.

"We are still in discussions with various parties, and are fully committed to protecting the interests of all shareholders," HKBN ( HKBNF ) said in a statement to Reuters.

I Squared's departure from the bidding race for HKBN ( HKBNF ) comes weeks after China Mobile acquired a 15.5% stake in the company in April from existing shareholder TPG.

($1 = 7.8288 Hong Kong dollars)