January 6, 2015 (Chinavestor)The Dow Jones Industrial Average plunged over 300 points as oil prices tumbled to over 5 year lows on Monday. The slide continued overnight as US oil futures fell below $50 with a negative price outlook. Oil stocks followed suit, CNOOC Ltd. (NYSE:CEO) fell as much as $2.98 on Monday. CNOOC Ltd. (NYSE:CEO) is China's offshore oil specialist with no refining capacity of her own and thus is hurting when oi prices fall. But Sinopec (NYSE:SNP) and Petrochina (NYSE:PTR) remained essentially flat on Monday because their downstream operation can theoretically make up for some of the losses on oil production.