Exxon Mobil, Chevron and other oil stocks were falling early Monday as crude prices tumbled after Israel spared Iran’s oil facilities over the weekend. The sharp drop ensured that oil stocks were also dragged lower, with Exxon down 1.7% and Chevron falling 1% in early trading. Marathon Oil fell 2.3%, Occidental Petroleum was 1.9% down and ConocoPhillips slipped 2.2%.