Argentina’s YPF SA surged the most on record following the election of outsider presidential candidate Javier Milei, who said he plans to privatize the state-owned oil and gas producer and remove controls stymieing the sector.

The driller’s American Depository Shares soared as much as 43%, the biggest intraday move since they began trading in 1993. Argentina’s government owns a majority stake in the company.

Milei has pledged a radical shakeup to fix decades of policy mismanagement in the inflation-slammed country, including dollarizing the economy, shutting the central bank and ending fuel pricing controls.

These measures and others have kept YPF and the Vaca Muerta shale basin on “the backburner,” Bloomberg Intelligence oil analyst Fernando Valle said. Argentina’s shale patch has vast untapped potential that has been limited by bottlenecks.

In theory, Milei’s plans should improve YPF’s margins and attract foreign direct investment. “It’s a matter of whether he can achieve it,” Valle said.

Independent producer Vista Energy, the Mexico-listed shale developer focused on Vaca Muerta, also rose Monday.

At the same time, Milei’s efforts in the oil sector could be derailed by the $16 billion that Argentina was ordered in September to pay over its contentious re-nationalization of YPF in 2012. Litigation funder Burford Capital, which backs the entities a US judge said are owed the award, didn’t reply to a request for comment.

(Updates with additional details beginning in the second paragraph)