Main index rises more than 1% after bumper results from Riyad Bank spark surge in banking stocks.
Saudi Arabia's main index gained more than 1 percent as banking stocks rallied after Riyad Bank beat expectations with its second-quarter profit.
Riyad Bank jumped 5.07 percent - its biggest one-day gain in almost two months - after it said its profit in the three months to June 30 climbed 6.8 percent, topping most forecasts in a net profit survey by newswire Reuters last month.
The index, the Gulf region's worst performer this year, advanced 1.12 percent to 9,483.23 points. It was down 15 percent this year to Saturday's close.
Other banking stocks also gained, with Al-Rajhi Bank jumping 3.51 percent, Samba Financial Group 2.29 percent and SABB bank 4.57 percent.
Dubai's index closed lower for a third trading day, easing about 1.5 percent as all traded stocks decline on retail selling.
Emaar Properties dropped 1.86 percent and Dubai Financial Market Co 2.35 percent. The measure shed 1.48 percent to 5,427.45 points.
"We are in a retail-driven market, which will likely be flat this month. Second-quarter earnings have already been factored into the share prices," said Amr Diab, head of sales at EFG-Hermes.
Abu Dhabi's index closed higher as Aabar Petroleum Investments Co surged for a fifth trading day.
Aabar soared 9.3 percent, extending five days of gains to more than 30 percent. The firm's board is set to consider on Monday issuing a convertible bond to an Abu Dhabi-based strategic investor.
Aabar said it is not aware of any additional news that could be driving up its share price.
"We are unaware of any data or important information that may affect our share price," Aabar said in a statement to the Abu Dhabi bourse on Sunday. The stock had jumped 26.35 percent in the four trading days to Thursday.
Emirates Telecommunications Corp (Etisalat) also added 0.75 percent, leading the index 0.14 percent higher to 5,087.96 points.
Oman's main index closed higher for a fifth trading day as investors snapped up shares on expectations of strong corporate earnings.
The Gulf region's best-performing index this year gained 0.62 percent to 11,705.32 points.
Bank Muscat rose 0.88 percent and Oman Telecommunications Co (Omantel) 1.48 percent.
Analysts in a Reuters net profit survey last month said they expected profit of the country's two biggest firms by market value to grow at least 24 percent.
"The expectation is that second-quarter results will be higher than forecast. I expect the index could cross 12,000 points this week," said Khalid Abdul Nabi, vice-president of brokerage at Gulf Investment Services.
Kuwait's index, which has fallen in all but one of the last eight trading days, declined as retail investors sold banking stocks before the summer holidays amid thin trading.
Kuwait's measure lost 0.71 percent to 15,267.10 points as Kuwait Finance House fell 1.43 percent andGulf Bank of Kuwait 1.54 percent.
"The trading volumes and value are very low today probably because of the summer," said Abdulmohsen Al-Bahar, a portfolio manager at Kuwait Gulf Consulting Co.
"The market will likely remain flat for the next month as the second-quarter results are released," he said.
Investment companies that focus on equity investments in the Gulf could take a hit, he said.
Qatar National Bank, up more than 30 percent this year to its closing price last week, dropped 4.77 percent, pushing the index down 0.78 percent to 12,066.77 points.
Qatar's index is the second-biggest gainer in the Gulf region this year after Oman, up almost 27 percent this year to Thursday's close.
In Bahrain, Al Salam Bank fell 2.19 percent after posting a decline in second-quarter profit. The index shed 0.14 percent to 2,864.50 points.