Chevron has posted a deeper-than-expected loss due to the oil price rout and tighter refining margins.
The company swung to a loss of $725m (£495.4m) in the first quarter, or 39 cents per share, from a profit of $2.6bn, or $1.37 per share a year earlier.
It posted revenue of $23.55bn during this period, compared to $34.56bn a year ago.
Analysts had expected Chevron to post a loss of 20 cent per shares, while its revenue shrank to $21.4bn.
“Our upstream business was impacted by a more than 35 per cent decline in crude oil prices," John Watson, chief executive of Chevron, said.
"Our downstream operations continued to perform well, although overall industry conditions and margins this quarter were weaker than a year ago."
"We continue to lower our cost structure with better pricing, work flow efficiencies and matching our organizational size to expected future activity levels."
Upstream operations posted a loss of $850m in first quarter 2016, compared to a loss of $460m a year earlier.
The average sales price for a barrel of oil was $26, down from $43 a year ago.
Oil production came in at of 701,000 barrels per day, up 2,000 barrels per day from a year earlier.