Chevron warns of sharply lower refining margins

SAN FRANCISCO (MarketWatch) -- Chevron Corp. [cvx: s], in its interim quarterly update, said late Thursday it faces "significantly lower" results from its refining and marketing operations in the second-quarter compared with the first quarter. Without providing specific estimates, it also said that while higher oil prices boosted earnings in its exploration and production activities, the gains were "largely offset by substantial unfavorable currency effects." Chevron, part of the Dow Jones Industrial Average, is slated to report its second-quarter results on July 31. Chevron shares closed Thursday with a 30-cent gain at $63.08.