RIYADH: The Saudi stock market started the first trading session of the week in negative territory following the shift in oil prices last week, which has caused investors to become concerned. The Tadawul All Share Index opened 0.35 percent lower on Sunday at 12,100, while the parallel Nomu added 0.54 percent at 21,441, as of 10:08 a.m. Saudi time. Saudi oil giant Aramco