Climate Action 100+, whose 450 members manage more than $40 trillion in assets and focus on engaging with companies which produce high levels of greenhouse gas emissions, said it would now look to step up talks with Pemex.
"Pemex has been added to the list of firms engaged through Climate Action 100+ as part of a standard periodic review process," a spokesman for Climate Action 100+ told Reuters.
The decision to add Pemex, a top issuer of emerging market bonds, follows engagements with listed companies including Royal Dutch Shell and BP, both of which have recently announced new long-term strategies in response to climate change.
Concerted pressure by the group has also helped bring about change at a number of other companies, among them Nestle, Maersk and HeidelbergCement, which have committed to net zero carbon emissions by 2050.
The Pemex engagement will be led by asset managers Federated Hermes and BlueBay Asset Management, with other members of CA100+ currently being canvassed about formally joining the group.
"We expect more from Pemex," said Jaime Gornsztejn, who leads engagement with Latin American companies for Federated Hermes. The asset manager's stewardship team advises clients with more than $1 trillion in assets on corporate governance issues.
"It's such a crucial issue for any oil and gas company for the long term wealth creation," said Gornsztejn. "That's why we expect strongly a shift on climate change by senior management and the board."
Pemex did not immediately respond to a request for comment.
Under Mexico's previous government, the company had laid out targets to reduce emissions, but under the new administration of President Andres Manuel Lopez Obrador it has not reaffirmed those goals.
Climate Action 100+ was launched in late 2017 with the aim of engaging with companies to curb emissions and strengthen governance and climate-related financial disclosures.
Earlier this year, the world's largest asset manager, BlackRock, also joined the group.
By Simon Jessop and Stefanie Eschenbacher