SEOUL (Reuters) - HSBC Holdings (HSBA.L: Quote, Profile, Research), whose $6.3 billion (3.15 billion pound) bid to buy Korea Exchange Bank (KEB) (004940.KS: Quote, Profile, Research) has stalled over a legal saga, pledged on Tuesday to keep KEB listed and name local directors if the acquisition goes through.

The pledges, made to KEB's labour union, are seen as an expression of HSBC's commitment for KEB ahead of the July 31 deadline for the offer to buy a 51 percent stake in KEB from U.S. private equity house Lone Star LS.UL.

"In the event of HSBC's acquisition of KEB's majority stake, HSBC and KEB labour union declare to exert all efforts to allow KEB to take a new leap forward and become a global bank", HSBC and the union said in a joint statement.

Their agenda includes maintaining KEB's name and its listing status on the local stock exchange, employment protection and name the majority of board directors among Koreans.

HSBC is waiting for an approval from South Korean regulators which have said the decision could come only after legal disputes over Lone Star's 2003 purchase of KEB are resolved.

The deadlock over the KEB sale has raised speculation about a possible collapse of HSBC's acquisition and talk that top local lender Kookmin Bank 060000.KS would jump into the bidding. KEB's labour union, which fears massive job cuts should a local rival take over the bank, has supported HSBC's bid.

HSBC last September agreed to buy 51 percent of KEB, South Korea's No. 6 bank, in a deal that could propel the UK-based bank into the top ranks of Asia's third-largest banking market.

(Reporting by Rhee So-eui; Editing by Keiron Henderson)