QNB's share price fell up to 8.7 percent before retracing some of those losses. The stock is down 0.8 percent at 138.50.
Investors are cashing in on Thursday's gains, said Hani Girgis, assistant chief dealer at Dlala brokerage, adding that the shares would be released in two weeks, with a capital increase of 25 percent at 100 riyals per share.
The Qatar benchmark slipped 1.7 percent to 8,499 points — its lowest close since April 5.
The long-term outlook for the country, however, is upbeat.
"There's a lot of valuation in the country, with the growth of the companies," said Robert Pramberger, acting head of asset management at Doha-based investment company The First Investor.
"Getting in at current prices would be good, because the market will be up 20 percent by year-end," he said.
Flagship Dubai property developer Emaar Properties weighed on Dubai's index, taking the edge off Thursday's yearly high as investors booked profits.
Emaar fell 1.4 percent ahead of quarterly earnings, released after the market close. It posted a 45 percent drop in first-quarter net profit.
"The market tends to drift off during Western Bank Holidays. Bit of profit taking ahead of Emaar numbers," said Matthew Wakeman, EFG-Hermes managing director for cash and equity-linked trading.
The benchmark closed 1 percent lower at 1,665 points, its first fall in 10 sessions.
Abu Dhabi's benchmark ended almost flat at 2,712 points, edging toward to a 10-week closing high.
Saudi Arabia's index rose for third day as Saudi Electricity Company (SEC) and Rabigh Refining and Petrochemical Company (PetroRabigh) supported.
SEC gained 5 percent and hit a three-week high.
"The market is comfortable but we don't see a catalyst in the near future," said a Riyadh-based trader on condition of anonymity, adding that the trading range of 100 points, set since March-end, is expected to hold.
"All the news is out, earnings were very good but expected, especially from petrochemicals."
PetroRabigh gained 6 percent after Credit Suisse upgraded it to "outperform" from "neutral."
The Tadawul All-Share Index (TASI) gained 0.36 percent to close at 6,614.17 points. The stock market turnover reached SR5.92 billion on Sunday.
Kuwait's Mobile Telecommunications Co. (Wataniya) closed at a more than two-year high after its first-quarter earnings beat expectations, helping boost Kuwait's index to a two-month high.
Wataniya rose 5.2 percent after posting first quarter net profit of 285 million dinars, up from 16 million dinars from the year-earlier period. In a surprise move, it announced earnings per share of 568 fils as compared to 32.34 fils in the first quarter of last year.
"The fact that they've revalued price, means nothing to the trader," said a Kuwait-based trader on condition of anonymity. "I doubt they're going to be giving out dividends."
The benchmark edged up 0.03 percent to 6,445 points — its highest close since Feb. 24.
The Omani index slipped 0.1 percent to 6,347 points.
The Bahraini measure ended flat at 1,401 points.
