Climate activists have bombarded Exxon Mobil’s top shareholders with calls and emails, urging them to vote against the reelection of chief exec Darren Woods and lead independent director Kenneth Frazier at an upcoming shareholder meeting.

Blackrock and Vanguard Group hold more than 13 per cent of Exxon share combined.

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Exxon is currently embroiled in battle with activist hedge fund Engine No. 1 over four seats on the 12-member board, as well as the company’s future direction.

The fund has criticized Exxon’s poor returns from heavy spending on fossil fuels and lack of a clear transition to cleaner fuels.

If the activists are successful in lobbing Blackrock and Vanguard to vote against the pair, the move could boost the hedge fund’s fight to seat four candidates on the oil giant’s board.

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BlackRock and Vanguard declined to comment on their stance. Both have signed the Net Zero Asset Managers Initiative, vowing to press portfolio companies to achieve net zero emissions by 2050 or sooner.

Exxon spokesman Casey Norton said the company supports the Paris Agreement on climate change, is focused on investments to lower carbon emissions in high-emitting sectors such as heavy industry and power, and is “the industry leader in carbon capture and storage.”

Exxon is “developing innovative solutions needed to help achieve society’s goal of a lower-carbon future,” Norton said, adding that conversations with investors have been constructive.

Exxon, the top US oil firm, in recent months has expanded its board, pledged to increase spending on lower-carbon initiatives and lower the intensity of its oilfield greenhouse gas emissions.

However, it has not set 2050 targets as its European peers have done.