Gulf shares advanced as regional investors gained confidence from rising global markets and as banks started refunding participants in the Drake & Scull International initial public offering.

Oman's Muscat Securities Market 30 Index rose 0.6 per cent, rebounding from yesterday's slump, the biggest since January. "The rebound in international markets is helping regional investors' confidence," Motaz Irshaid, institutional sales trader at Al Futtaim HC Securities in Dubai, said.

Oman International Bank rose for the first time in eight days.

Oman International Bank, the Muscat-based lender with branches in India and Pakistan, climbed 1.5 per cent to 3.848 rials.

Saudi Arabia's Tadawul All Share Index retreated 0.4 per cent, bringing the six-day drop to four per cent. The Kuwait Stock Exchange Index and Qatar's Doha Securities Market Index gained less than 0.1 per cent. The Bahrain All Share Index lost 0.7 per cent.

Gulf Petroleum Investment (GPI KK) advanced 1.4 per cent to 375 fils. The Kuwaiti oil investment company said second-quarter net income surged 61 per cent to 2.56 million dinars, according to a statement posted on the web site of Dubai's bourse.

National Mobile Telecommunications Co rose 2.8 per cent to 2,180 fils. The Kuwaiti phone company bought by Qatar Telecom QSA last year said second-quarter net income rose 47 per cent to 26.5 million dinars.

Qatar Islamic Insurance Co climbed 1.9 per cent to 73.4 riyals. The company that sells non-life policies compliant with Islamic Shariah law said first-half net income more than doubled to 49.6 million riyals.

Meanwhile, Saudi Arabia's stock market operator said yesterday that the bourse, the largest in the Arab world, will publish the names of investors next months with stakes of five per cent or more to boost transparency. The bourse is dominated by day traders and has been trying to improve transparency and gain more institutional investors since a market crash in 2006.

The Saudi market – the worst performer in the Gulf this year – has been tainted by allegations of insider trading and manipulation of stock prices. A list of the largest shareholders in publicly traded Saudi firms would be updated at the close of trading each day beginning on August 16, the operator, Tadawul, said in a statement.

"This service by Tadawul aims to increase the level of transparency and disclosure in market dealings," it said. "Investors would have information about who owns large holdings… this would assist in enhancing confidence among investors to make them take correct investment decisions."

The new disclosure rule could be interpreted negatively by Saudi investors, some of whom may not want to have their holdings made public, said John Sfakianakis, chief economist at Sabb bank, HSBC's Saudi affiliate. "On the regulatory side this is a positive step… but the market might perceive this with a certain ambivalence," he said.

"Some people might not want to reveal their ownership so they might decide to sell." When Saudi Arabia decided to cancel an evening trading session in late October 2006, the index tumbled almost 25 per cent in less than two weeks.

The index also dropped more than four per cent in one day earlier this month after the exchange said it plans to adopt a more flexible pricing system to better reflect what investors deem to be the fair value of stocks. The new disclosure rule could help the regulator dispel rumours that big retail traders are behind rapid fluctuations in share prices, a common assumption in the market, Sfakianakis added.