UPDATE 8: Saudi's index closes 3.61% down, banks and petrochems lead loss.
Qatar's main index closed 1.17 percent lower at 6,473 points as bank stocks weigh on the Gulf Arab bourse on its first day as the Qatar Exchange.
NYSE Euronext, owner of the New York Stock Exchange, will take a 20 percent stake in the newly created Qatar Exchange for $200 million, while Qatar will own the rest, the partners said on Friday. Qatar Exchange is the successor to the Doha Securities Market.
Qatar Islamic Bank took the most points off the index, falling 3.39 percent. Al Khaliji Bank fell 4.14 percent.
"It's a correction that has started after the market went up considerably over the past few months," says Mohammed Yasin, Shuaa Securities chief executive.
The Qatar index has lost 12 percent since the start of last week, having risen more than 70 percent since the beginning of March.
"It's going to be a very low volumes until we see some indication of the company results in early July," he says.
Saudi's benchmark index closed down 3.61 percent at 5,741 points, its largest one-day loss since April 19.
Heavyweight Al Rajhi Bank fell 3.7 percent, while Saudi Basic Industries Corp (SABIC) declined 3.52 percent.
Markets in the UAE closed sharply lower in thin trading, with real estate and bank shares leading losses.
In Abu Dhabi, Aldar Properties took the most points off the index, declining 5.58 percent. Abu Dhabi Commercial Bank fell 4.85 percent.
Dubai's Emirates NBD fell 4.89 percent, while Emaar Properties lost 4.44 percent.
Shares in Deyaar fell 6.9 percent after its chairman Nasser Al Sheikh resigned from his post.
Abu Dhabi's main index fell 1.68 percent to 2,751 points.
The Dubai benchmark slipped 3.51 percent to 1,943 points.
In Kuwait, shares in National Bank of Kuwait slipped 2.99 percent.
NBK said on Thursday it had raised its stake in Boubyan Bank to more than 12 percent, becoming the third-largest shareholder in the Islamic lender to help boost its Sharia-compliant business.
The index closed down 1 percent at 8,288 points.
Oman's main index closed up 0.55 percent at 5,721 points.
Bank Muscat added the most points to the index, rising 2.67 percent. Raysut Cement gained 2.33 percent.
Bahrain's main index closed 0.3 percent higher at 1,628 points.