Valero Energy is trading 10.03% down now at $348.76, as oil prices fell amid investor reassessment of the Iran conflict and prospects for diplomacy after Democrats won control of Congress. - The energy sector is down while major U.S. indexes are higher. - No company-specific negative announcement explaining the drop surfaced in the search. - Valero’s earlier Houston refinery acquisition would add planned capacity and does not clearly explain today’s decline.