RIYADH, Broadcasting News Corporation : Saudi Arabia’s main index ended the last trading session of the week lower as investors kept a keen eye on the unstable oil prices this week. The Tadawul All Share Index slipped 0.11 percent to end Thursday at 11,757, while the parallel market Nomu finished almost flat at 20,223. In the energy sector, Brent crude reached $93.22 per barrel, while WTI crude traded at $87.61 per barrel as of 3:14 p.m. Saudi time. Saudi oil giant Aramco ended the session with a 0.14 percent increase, while Rabigh Refining and Petrochemical Co. edged up 1.21 percent. The Saudi National Bank, the Kingdom’s largest lender, dropped 0.77 percent, while Saudi British Bank declined by 2.31 percent. The Kingdom’s most valued bank Al Rajhi fell 0.71 percent, while Alinma Bank shed 0.26 percent. Despite leading Wednesday’s fallers, Tihama Advertising and Public Relations Co. surged 9.81 percent, topping the market, after receiving the Capital Market Authority’s clearance to hike its capital by 700 percent. Dar Al Arkan Real Estate Development Co. declined 2.87 percent to lead the fallers, closely followed by Riyad REIT Fund with a decline of 2.76 percent.