(Adds capital spending forecast, throughput, background)
April 29 (Reuters) - Valero Energy Corp on Wednesday reported a first-quarter loss due to $2 billion in inventory writedowns and cut its investment budget for the year, as the independent U.S. refiner grapples with an unprecedented drop in demand for its products.
U.S. oil prices last week turned negative for the first time in history, underscoring the extent to which the COVID-19 pandemic has damaged demand, as flights and other transportation around the world remain grounded with people staying at home.
Valero's throughput, the amount of crude oil processed by its refineries, dropped 1.8% to 2.8 million barrels per day, its lowest in 18 quarters.
The company's refining margin fell 9.7% to $1.86 billion, while quarterly revenue dropped about 9% to $22.1 billion, the lowest in 3 years.
The company also said on Wednesday it now expects capital investments for 2020 to be about $2.1 billion, $400 million lower than its original forecast.
Earlier this month, Valero withdrew all of its earnings forecasts for the year, citing the economic ramifications of the pandemic and a price war launched by some oil-producing nations in March.
Valero's shares rose 3.6% in premarket trading along with other energy stocks, as U.S. oil prices climbed on Wednesday.
Net loss attributable to stockholders was $1.85 billion, or $4.54 per share, for the three months ended March 31, compared with a net income of $141 million, or 34 cents per share, in the year-ago period.
Excluding the $2 billion writedown charge, caused by the declining value of its refining inventory, Valero reported adjusted net income of 34 cents per share for the quarter.
Reporting by Shariq Khan in Bengaluru; Editing by Devika Syamnath