RIYADH: Saudi Arabia’s main stock index gained 0.3 percent on Tuesday, buoyed by chemical giant Saudi Basic Industries Corp. which posted higher second-quarter profits. TASI closed the session at 12,330, while the parallel Nomu market added 0.6 percent to 22,199. Abu Dhabi and Dubai advanced by 0.2 and 1.1 percent, respectively, while Qatar, Oman, and Kuwait all lost between