Major oil distributor and refiner Mitsubishi Oil Co. posted a 3.8 billion yen operating loss and 2.8 billion yen pretax loss for the April-September period, suffering from decreasing oil demand in the economic slump and dwindling prices of oil products, company officials said Monday.

The company, which last week announced a merger plan with Nippon Oil Co., predicted a 6.2 yen operating loss and a 9 billion yen pretax loss for fiscal 1998. Its midterm sales of jet fuels, kerosene, light oils and coals all decreased compared with the previous year, company officials said.

Sales volume of oil products dropped 1.8 percent to 14.1 million kiloliters in the six-month period, with the sales shrinking 7.1 percent to 482.9 billion yen, the company said.