California’s climate-disclosure laws set to reshape corporate reporting landscape in 2026

California’s twin climate-disclosure statutes, the Climate-Related Financial Risk Act (SB 261) and the Climate Corporate Data Accountability Act (SB 253), are set to reshape reporting expectations for large companies that do business in the state, with the first regulatory filings due in 2026.

According to the original report, SB 261 and SB 253 were signed in 2023, took effect in 2024 and impose high thresholds intended to capture organisations with substantial economic activity in California while excluding most small businesses and charities. SB 261 applies to companies with more than $500 million in annual revenue that conduct business in California; SB 253 targets firms with more than $1 billion in revenue. Industry data shows these thresholds reach several thousand entities , estimates range around 5,000 to 5,300 companies , including both domestic and international firms with operations or sales in California.

Reporting scope and timing
SB 261 requires companies to disclose climate-related financial risks and the governance, strategy and risk-management processes they use to address those risks. Reports are to be made publicly available and, according to guidance tied to the law, should follow the Task Force on Climate-related Financial Disclosures (TCFD) framework or an equivalent standard. The first SB 261 submissions are due on 1 January 2026 and will cover the 2025 calendar year, with annual filings thereafter. Administrative penalties for non-compliance have been reported as reaching up to $50,000 per reporting year.

SB 253 mandates public disclosure of greenhouse‑gas emissions. Companies must report Scope 1 (direct) and Scope 2 (purchased energy) emissions beginning in 2026, with Scope 3 (value‑chain) disclosures phased in from 2027. The law requires alignment with the Greenhouse Gas Protocol and third‑party verification of emissions data. Reported enforcement provisions include administrative penalties for failing to comply, with published commentary noting potential fines up to $500,000 per reporting year. The California Air Resources Board (CARB) is charged with designing the online reporting platform, defining technical rules and setting the precise annual due dates.

Regulatory and commercial implications for industry
For industrial decarbonisation professionals, these laws create immediate operational and governance tasks. Companies within the revenue thresholds must establish or scale emissions accounting systems, extend data collection into supply chains for Scope 3, and secure accredited third‑party verifiers. The phased approach to Scope 3 is intended to give organisations time to build robust data pipelines, but industry sources warn the practical burden , including supplier engagement, data quality work and verification costs , will be significant.

The rules also increase transparency for investors, insurers and regulators by linking physical climate risks (for example heat stress, flooding and wildfires) and transition risks (policy change, market shifts, technological substitution) to corporate financial planning. According to the original report, firms must describe how those risks affect operations and long‑term planning and outline mitigation and adaptation measures.

Legal contest and commercial sensitivities
The new regime has not been uncontested. Reuters reported that Exxon Mobil filed suit in October 2025 in the U.S. District Court for the Eastern District of California, challenging both SB 253 and SB 261. Exxon argues the laws compel disclosure of proprietary information and violate constitutional protections. California officials had not commented publicly at the time of the report. The litigation highlights a persistent tension: regulators and investors seeking standardised, public climate data versus companies concerned about revealing competitively sensitive information and legal exposure.

Practical next steps for corporates
The company claims and industry analysis together suggest several priorities for affected firms. Businesses should:

• inventory operations and revenue exposure to confirm whether they meet California’s thresholds;
• map existing climate‑risk governance and emissions accounting frameworks against TCFD and the Greenhouse Gas Protocol requirements;
• begin supplier engagement and data collection for Scope 3 now to meet the 2027 reporting phase‑in;
• budget for independent verification and potential system upgrades to manage public disclosures;
• review legal exposure and disclosure strategies in light of ongoing litigation challenging the statutes.

The CARB implementation process will shape many operational details, from the reporting portal to verification standards and data‑access provisions. According to the original report, CARB will publish official instructions and the portal through its Corporate Greenhouse Gas Reporting Program pages as the 2026 deadlines approach.

For professionals charged with industrial decarbonisation, the new California rules represent both a compliance challenge and a strategic signal. Greater transparency is likely to accelerate market pressure for emissions reductions across supply chains, influence capital allocation and affect risk assessment by insurers and lenders. Firms that treat the requirements as a prompt to strengthen emissions governance, data integrity and supplier collaboration will be better positioned both to comply and to capture the business advantages of earlier, more credible decarbonisation action.