Saudi stocks jumped the most Saturday in more than five months amid high volumes as climbing oil prices boosted confidence in the Kingdom's economy. The stock benchmark Tadawul All Share Index rose 1.44 percent, its biggest gain since Sept. 17, to 7,481.27 points on the first trading day of the week with 551 million shares traded, compared with a six-month daily average of 290 million. Saudi Basic Industries Corp. (Sabic), the world's largest petrochemicals maker, advanced to its strongest level in more than seven months. The 152-member index rallied 1.4 percent last week, capping a 7-week winning streak, the longest since January last year. Sabic which has the heaviest weighting in the index, gained 3 percent to SR104.75, the highest level since Aug. 1. Oil rose for a third day in New York Friday, increasing 0.8 percent to $107.40 a barrel. Dar Al Arkan Real Estate Development Co. dropped 0.5 percent, the biggest decline this month, to 10.10 riyals. Saudi Arabia's second-biggest property company by market value had its credit rating downgraded to B+ from BB- and was placed on negative watch by Standard & Poor's.