Moody's on Tuesday downgraded Mexican state-oil giant Pemex's foreign and local currency ratings to Baa1 from A3.
"Moody's believes that Pemex's credit metrics will deteriorate further in the short to medium term as oil prices remain depressed, production continues to drop, taxes remain high, and the company's capex needs are financed with debt," Moody's credit officer Nymia Almeida said in a statement.
In response, Pemex said it had expected the downgrade since Aug. 25, and added that it had taken various measures to improve its finances, including renegotiating pension liabilities and cost-cutting.
The company also said that last June, it discovered new oil fields that could hold reserves of up to 350 million barrels.