March 6 (Reuters) - Argentina's national oil company YPF

swung to a net loss of $1.86 billion in the fourth quarter, the

firm said on Wednesday, driven largely by weaker sales and a

hefty impairment charge.

Revenues fell 9.7% to $4.194 billion from $4.645 billion in

the October-to-December period in 2022, it said in a statement,

despite the steady production increase from western Argentina's

massive Vaca Muerta shale formation, one of the biggest in the

world.

The company, one of Argentina's top domestic sellers of

refined fuels, took a $1.782 billion impairment charge to pay

for the deterioration of assets, it said.