Chevron Corp. shares slid 1.5% in premarket trade after the company swung to a loss for the second quarter as it booked impairment and other charges. Chevron said it had a net loss of $1.5 billion, or 78 cents a share in the quarter, after earnings of $571 million, or 30 cents a share, in the year-earlier period. The number includes $2.8 billion of impairment and other non-cash charges, partially offset by gains on asset sales of $420 million. Revenue tumbled to $29.3 billion from $40.4 billion. The FactSet consensus was for EPS of 32 cents and revenue of $28.3 billion. "The second quarter results reflected lower oil prices and our ongoing adjustment to a lower oil price world," Chief Executive John Watson said in a statement. Shares have gained 13% in the year to date, while the S&P 500 has gained 6%.