Dana Gas pulled the Abu Dhabi bourse lower for a second day amid investor uncertainty over how the UAE gas explorer plans to repay a US$1 billion sukuk due in October.
Dana, the most actively traded stock on the Abu Dhabi Securities Exchange (ADX), fell 8.1 per cent to 34 fils. Dana's shares have lost more than 15 per cent in the past two days.
The ADX General Index slid 0.8 per cent to 2,324.73 points.
Global markets reported marginal midday gains on the first day of trading after Standard & Poor's cut sovereign ratings for a number of countries in the euro zone, including France, on Friday.
Dubai stocks experienced a sell-off amid heightened political tension after Iran threatened to shut the Strait of Hormuz, a transit route for about a fifth of global oil trade.
"The tension is intensifying in the region," said Amjad Bakir, the head of equities at Mena Corp brokerage in Abu Dhabi. "Investors are solely reacting to the political headlines."
Dubai Financial Market Company, the only publicly stock exchange in the region, dropped 9.9 per cent to 68 fils. Emaar Properties, the region's largest developer fell 1.2 per cent to Dh2.41. The DFM General Index lost 1 per cent to 1,301.24.
Elsewhere in the region, Kuwait's measure was unchanged at 5,762.80. Bahrain's bourse added 0.6 per cent to 1,142.20. Oman's MSM 30 Index slipped 0.1 per cent to 5,633.99 and Qatar's QE Index was flat at 8,640.36. The Saudi Tadawul All-Share Index declined 1.1 per cent to 6,420.89.