RIYADH: A plunge in oil prices weighed on major Gulf markets on Monday, but Saudi Arabian stocks bucked the trend to close higher. Even as TASI the main index advanced by 0.6 percent to reach 13,543 points, the Kingdom’s parallel market, known as Nomu, shed 1.3 percent to 23,521 points. Stock exchanges of Qatar, Abu Dhabi, and Dubai dropped 1.6, 0.9, and 0.8 percent,