Supreme court justice Samuel Alito gained up to $2.9m from his fossil fuel interests between 2005 and 2024, a new review of financial disclosures shows.

The analysis from the non-profit advocacy group and judicial watchdog Court Accountability, shared exclusively with the Guardian, found that even at the lowest range of estimates, Alito gained almost $400,000 from his oil and gas interests since being tapped for the high court by George W Bush in 2005.

The findings come as the supreme court prepares to take up a case in which the oil companies Suncor Energy and Exxon asked the justices to find that federal law prevents subnational governments from filing lawsuits against fossil fuel producers for the climate-warming effects of their products.

The supreme court said this month it will hear oral arguments in the case on 5 October, the opening day of its new term. The Trump administration, which is siding with the oil companies, has asked for 10 minutes of argument time. Court Accountability and other groups have called for a Senate committee to investigate Alito, the sole supreme court justice with holdings in energy companies, and said he should recuse himself.

He and the court rejected those calls.

Supreme court ethics rules focus specifically on investments in companies named in court cases. In May, a supreme court spokesperson told NBC News that Alito is not required to recuse himself from the Suncor lawsuit as his holdings do not include the companies directly named in the case, Suncor and ExxonMobil.

But Lisa Graves, co-founder of Court Accountability who authored the new analysis, said Alito’s oil-tied wealth provides grounds to question whether Alito can impartially weigh in on cases affecting the entire fossil fuel sector.

“You might have real appreciation for how that industry has helped make it possible for you to perhaps buy a second home on the water, or live a [certain] lifestyle,” she said.

The Guardian has contacted the supreme court court and Alito for comment.

Mineral rights

Alito’s financial disclosures show his reported assets – excluding his home and other personal property – grew from about $1.1m in 2005 to between $3.4m and $8.4m by 2024. Federal financial disclosures report assets in broad value ranges.

During that period, his oil and gas holdings made him between $390,000 and $2.9m, Court Accountability’s review shows. Most of those gains came from a property in Grady county, Oklahoma, in which Alito’s wife, Martha-Ann, holds a mineral interest.

Graves said Alito may have undervalued the worth of this property, because in 2017, a relative of the Alito family sold an adjacent plot for $800,000. “It’s reasonable to assume that means the value of the Alito property would have increased to around $800,000,” said Graves, but he continued to report its value at $100,000 to $250,000.

The justice reported two windfalls from rental income on the property in 2019 and 2022, with gains of between $100,000 and $1m in both years.

Alito’s wife agreed to lease the plot of land to the private oil and gas company Citizen Energy in 2022, the Intercept first reported. In 2024, that company was acquired for more than $2bn by Validus Energy, in which hedge fund Elliott Investment Management holds a majority stake. Elliott was founded by Paul Singer, who ProPublica found had paid for a private jet ride Alito took in 2008 that the justice did not disclose. Alito later defended the trip, saying ethics rules did not require its disclosure.

No reporting or public documents indicate that a well has been drilled on the property, but a lease agreement shows the owners would have received three-sixteenths of the money from any oil extracted from the land.

“It raises concerns because you have a sitting justice who is hoping to get richer based on oil exploration of this land,” said Graves.

Another large portion of Alito’s fossil fuel gains came through inheritance. In 2004, the justice disclosed that he obtained a bequest of ExxonMobil stock valued between $100,000 and $250,000.

The Exxon stock was the highest value of any single liquid investment listed by Alito “by a good margin”, Graves said.

Alito appears to have since sold his stock in ExxonMobil, as indicated by the supreme court’s May statement to NBC News.

“But my view is that you shouldn’t be able to sell a stock just so you can sit on a case, even though that company’s profits have benefited you,” said Graves.

Alito is the only justice who has not yet submitted his 2025 disclosure document. The filing was due on 15 May. Justices can obtain a 90-day extension; if Alito received one, he should file the document this Thursday. Last year, he filed his disclosure in August.

Alito has had a variety of smaller investments in more than a dozen oil firms, including ConocoPhillips and its predecessor Phillips 66, Chevron and energy infrastructure company Kinder Morgan.

“A reasonable person would think if you’re invested in the industry that could benefit from the outcome of a lawsuit, then you could personally stand to benefit from the outcome, even if you don’t hold the stock in the specific company that happens to be the named plaintiff,” said Graves.

Alito’s record

Alito has a history of voting in favor of fossil fuel interests. In the landmark 2007 case Massachusetts v Environmental Protection Agency (EPA), he was one of four dissenting justices who argued greenhouse gas emissions could not be regulated under the Clean Air Act.

Then in June 2022, when the supreme court decided West Virginia v EPA, Alito joined Neil Gorsuch’s majority in arguing that the EPA lacked broad authority under the Clean Air Act to mandate a shift away from fossil fuels.

More recently, he joined the majority in two 2024 decisions that overturned the longstanding Chevron doctrine and could make it harder for agencies to defend expansive environmental regulations.

Alito has recused himself from other environmental cases. In January, he stepped away from a lawsuit focused on whether energy companies could be held responsible for Louisiana coastal degradation because he owns stock in ConocoPhillips, the parent company of a defendant in proceedings tied to the litigation.

In 2023, Alito also recused himself from considering a petition in the Suncor lawsuit, brought by the company and Exxon. That request was denied.

Later in 2023, the supreme court adopted its first-ever formal ethics code amid a slew of scandals involving senior rightwing justices. It states that justices should recuse themselves from cases where their “impartiality might reasonably be questioned”, though it allows them to make that decision themselves.

Though Graves harshly critiqued that ethics code, saying it is “toothless” and “not worth the paper it’s written on”, she said it should in theory prevent Alito from weighing in on Suncor v Boulder in October.

“His impartiality may be reasonably questioned in terms of his affinity towards the industry that has helped build his nest egg,” she said.