The United States is facing a national insurance crisis. In 2023, national insurance underwriting losses reached a 10-year high of $38 billion due to more frequent and intense weather-related disasters, reinsurance price increases, and related inflation.[1] To stay profitable amid increasing catastrophe losses, insurers have increased premiums nationwide and ended coverage in high-risk areas,[2] leaving many regions with inadequate protection.

Berkshire Hathaway’s (“Berkshire”) catastrophe losses have also escalated. Its estimated pre-tax losses reached $4.7 billion in 2022 and $1.5 billion in 2024.[3] Early data from 2025 estimates Berkshire’s losses from the California wildfires at $1.1 billion.[4] This follows a global trend: Munich Re reports insured global catastrophe losses reached $140 billion in 2024, marking the fifth consecutive year of losses exceeding $100 billion.

As one of the world’s largest property and casualty insurers,[5] Berkshire is amplifying the risk of catastrophic weather-related losses by continuing to invest in and underwrite significant levels of greenhouse gas (GHG) emitting activities. As reported by the Wall Street Journal, while most property and casualty insurance companies reduced the proportion of fossil fuels in their portfolios to a median of 1.8% in 2023 from 3.4% in 2014, Berkshire was one of two insurers that dramatically increased such investments. This drove the industry’s portfolio exposure up from 3.8% in 2014 to 4.4% in 2023,[6] above the S&P 500’s energy sector market capitalization of 3%.[7] Berkshire also ranks at the bottom of a survey of the 30 largest global insurers, as one of only five insurers to earn a score of zero for failing to put in place policies to reduce investments in and insuring of high-emitting activities.[8]

The first step to reducing GHG emissions is to measure them. By disclosing the GHG emissions from its investments in and insurance of high-carbon companies, Berkshire would gain critical insight into its contribution to future catastrophic weather-related losses and the associated portfolio risks. Initiating disclosure would also prepare Berkshire for regulatory disclosure requirements at both the state and international levels.

Other insurance companies are taking action. Travelers,[9] AIG,[10] and The Hartford[11] have begun disclosing GHG emissions from their investment activities. Most major European insurers, including AXA,[12] Allianz,[13] Zurich Insurance Group,[14] and Swiss Re[15] are also disclosing invested emissions. In contrast, Berkshire does not disclose its GHG emissions despite its substantial exposure to high-emitting companies.

[1] https://www.insurancejournal.com/news/national/2024/03/07/763884.htm

[2] https://www.ft.com/content/7745d8ba-d498-4b1c-b877-e42a691b954f

[3] https://www.berkshirehathaway.com/2024ar/2024ar.pdf

[4] https://www.berkshirehathaway.com/qtrly/1stqtr25.pdf

[5] https://www.spglobal.com/market-intelligence/en/news-insights/articles/2025/10/the-world-s-largest-property-and-casualty-insurers-2025-93316415

[6] https://www.wsj.com/us-news/climate-environment/the-two-big-insurers-still-betting-on-fossil-fuels-fa31bb15

[7] https://www.schwab.com/learn/story/stock-sector-outlook

[8] https://insure-our-future.com/scorecard/

[9] https://asset.trvstatic.com/download/assets/Travelers_TCFDReport2024.pdf/db0c21f6147211f093342a4bfe896913

[10] https://www.aig.com/content/dam/aig/america-canada/us/documents/about-us/report/aig-sustainability-report-2024.pdf

[11] https://assets.thehartford.com/image/upload/cdp_project_submission.pdf

[12] 8b8dfa69-13e3-4c34-bae3-8fb939102a2d_axa_climate_and_biodiversity_report_2024_va.pdf

[13] https://www.allianz.com/content/dam/onemarketing/azcom/Allianz_com/investor-relations/en/results-reports/annual-report/ar-2024/en-allianz-group-annual-report-2024.pdf

[14] https://view.officeapps.live.com/op/view.aspx?src=https%3A%2F%2Fedge.sitecorecloud.io%2Fzurichinsur6934-zwpcorp-prod-ae5e%2Fmedia%2Fproject%2Fzurich%2Fdotcom%2Fsustainability%2Fdocs%2Fsr-2024-data.xlsx&wdOrigin=BROWSELINK

[15] https://www.swissre.com/dam/jcr:84dfce47-e0fe-468a-9f57-55c1c74c9b3a/2024-sustainability-report-CTP-extract-en.pdf