Exxon Mobil Corp joined a parade of oil companies posting downbeat results as it posted a first-quarter loss after a nearly $3 billion inventory writedown on plunging oil demand and low prices. Oil giants have largely reported losses because of weaker margins and writedowns from an oil glut that has has sent prices to historic lows. Exxon said profit fell in every business apart from chemicals, which benefited from low oil and gas prices.
