NEW YORK, May 29 — US energy giant ConocoPhillips announced today that it is acquiring competitor Marathon Oil for US$22.5 billion in the latest big petroleum merger consummated in spite of rising concerns about climate change.

The all-stock transaction combines two familiar Houston-based oil players, expanding the larger ConocoPhillips' US holdings and potentially providing massive cost savings.

The acquisition "further deepens our portfolio and fits within our financial framework, adding high-quality, low cost of supply inventory," ConocoPhillips chairman and chief executive officer Ryan Lance said in a company statement.

The deal, which includes the assumption of US$5.4 billion in Marathon debt, is the latest in a series of acquisitions in the US oil sector, extending the lifespan of petroleum at a time when climate change advocates are pressuring producers to transition to carbon-free energy.

It will enable ConocoPhillips to strengthen its position in shale oil and gas-rich regions such as the Bakken Basin in the northern United States, the Eagle Ford fields in Texas and the Permian Basin in Texas and New Mexico.

A company presentation highlighted the proximity of Marathon's acreage in these regions to ConocoPhillips' holdings, creating potential economies of scale.

The deal should see ConocoPhillips achieve savings of US$500 million in the year after completion, according to a ConocoPhillips press release, largely due to reduced administrative and production costs.

ConocoPhillips pledged to return excess cash to shareholders, saying it plans to boost its dividend by 34 per cent and expects more than US$20 billion in share repurchases over the next three years.

The deal, which is expected to close in the fourth quarter of this year, gives Marathon Oil shareholders 0.255 shares of ConocoPhillips common stock for each share of Marathon Oil common stock.

That represents a 14.7 per cent premium over Marathon Oil's closing price on Tuesday.

A note from JPMorgan Chase said the takeover solves a challenging outlook for Marathon, which has done "an excellent job in the field" but would have needed to do more "to address inventory renewal over time."

The 15 per cent premium was an "attractive alternative", said the JPMorgan note.

Shares of Marathon jumped 9.1 per cent in morning trading, while ConocoPhillips fell 3.1 per cent.

Chevron deal speed-bump

ConcoPhillips is the third biggest US oil company by market capitalisation after ExxonMobil and Chevron, both which announced major petroleum-focused takeovers last year.

The deals have come in spite of rising global recognition of climate change, resulting in a landmark agreement at December climate talks in which nearly 200 countries agreed that the world will be "transitioning away from fossil fuels" in order to achieve net-zero emissions by 2050.

However, while US oil companies have faced pressure from climate-focused NGOs and investors to accelerate climate-friendly investments, demand for conventional petroleum has remained firm.

The ConocoPhillips deal follows ExxonMobil's US$60 billion takeover of Pioneer Natural Resources, which closed earlier this month.

Chevron's proposed US$53 billion takeover of Hess cleared one hurdle on Monday after Hess shareholders voted to approve the transaction.

However, the Hess deal hit a speedbump earlier this year due to a challenge by ExxonMobil over the transaction's effect on ExxonMobil's holdings in Guyana.

Chevron has indicated it could walk away from the deal if arbitration is unsuccessful. — AFP