Oman's Renaissance Services  has pulled the planned $500 million initial public offering of its oilfield services unit Topaz on valuation concerns and growing regional unrest, a source familiar with the matter said.

The order books for Topaz Energy and Marine, which was set for a London listing, was not fully covered by institutional investors, a banking source close to the deal told Reuters on Thursday.

The company may come back with the offering later, but has not given a timeframe, he said.

"They (Renaissance) want to look at other options but have not specified what exactly they plan to do," he said.

Topaz -- one of the biggest oil services companies in the Middle East - launched the process for its $500 million London-listed IPO earlier in March with a price range of 170 pence to 230 pence.

The IPO had an implied market value of between $1.5 billion and $1.9 billion for the Dubai-based company.

During a call with reporters at the time, Topaz chief executive Fazel Fazelbhoy said the offering would have given the oilfield services company a market capitalisation of $1.7 billion, making it eligible for inclusion in the FTSE 250.

Fazelbhoy was not immediately available for comment on Thursday.     

JP Morgan and Bank of America Merrill Lynch were the bookrunners for the planned IPO.     

Renaissance bought Topaz, which last year had revenues of $408 million and a profit of $70 million, through a share swap in 2005.

Shares of Renaissance have lost nearly 10 percent of their value on the Muscat bourse in the last two trading sessions amid fears that the IPO may be pulled. - Reuters