The Saudi stock market started positively but failed to sustain and closed 0.18% lower at 6,323.95 points. Although market and petrochem leader Sabic lost 0.28%, the petrochem sector index added 0.33%. Wataniya Insurance Company surged 6.73% to Dhs55.50. Yansab National Petrochemical Co. bucked the trend and closed 2.60% higher at SR39.40.