California has taken a major step toward implementing its corporate climate disclosure requirements. On October 12, 2026, the California Office of Administrative Law (OAL) approved the state's initial climate disclosure regulation, officially establishing November 10, 2026, as the first reporting deadline under the Climate Corporate Data Accountability Act (SB 253).

The approval follows months of regulatory revisions and provides greater certainty for thousands of large U.S. companies preparing to disclose their greenhouse gas (GHG) emissions. While legal challenges remain, the reporting requirements under SB 253 are currently enforceable, making the upcoming deadline a priority for corporate sustainability and compliance teams.

California Confirms Its First Mandatory Emissions Reporting Deadline

The California Air Resources Board (CARB) initially approved the regulation in February 2026, proposing an August 10 reporting deadline. However, CARB subsequently withdrew the regulation for revisions, including clarifications to applicability requirements and a three-month extension.

With the OAL's approval on October 12, the regulation became effective immediately, formally confirming the November 10 deadline. The initial regulation establishes administrative fees, clarifies certain applicability definitions, and sets the first reporting deadline. Additional rules governing reporting in 2027 and beyond are still being developed.

Which Companies Must Comply?

California's climate disclosure framework includes two major laws, originally enacted in October 2023 and amended in September 2024:

SB 253 — Climate Corporate Data Accountability Act

Applies generally to U.S.-formed public and private companies that do business in California and have annual revenues exceeding $1 billion. Covered companies must disclose their greenhouse gas emissions annually, beginning with Scope 1 and Scope 2 emissions in 2026 and expanding to Scope 3 emissions in 2027.

SB 261 — Climate-Related Financial Risk Act

Applies generally to U.S.-formed companies doing business in California with annual revenues exceeding $500 million, subject to statutory exclusions. The law requires biennial disclosures covering climate-related financial risks and measures taken to reduce or adapt to those risks.

However, SB 261 remains subject to a federal court injunction, meaning CARB is not currently enforcing its reporting requirements. The injunction does not apply to SB 253. Importantly, companies do not need to be headquartered in California to fall within the scope of these laws. The initial regulation also clarifies how revenue and California business activity are assessed, making entity-level applicability reviews particularly important for companies with complex corporate structures.

What Companies Must Report in November 2026

For the first reporting cycle, companies subject to SB 253 must address two categories of greenhouse gas emissions:

• Scope 1 emissions: Direct emissions from sources owned or controlled by the company, such as fuel combustion in company-operated facilities and vehicles.

• Scope 2 emissions: Indirect emissions associated with purchased electricity, steam, heating, and cooling.

Scope 3 emissions, which include indirect emissions throughout a company's value chain, are not required for the November 2026 submission. These disclosures are scheduled to begin in 2027.

CARB has also introduced transitional flexibility for the first reporting cycle.

Companies may use qualifying emissions information they already possessed or were collecting as of December 5, 2024, including information from existing sustainability reports and voluntary disclosures.

Companies that did not possess Scope 1 or Scope 2 emissions data and were not collecting such information as of December 5, 2024, may instead submit a statement on company letterhead explaining their circumstances and why an emissions report is not being submitted.

CARB has also confirmed that it will accept 2026 submissions without third-party limited assurance. These accommodations are specific to the initial implementation period and should not be interpreted as permanent exemptions from the law.

How Companies Can Submit Their Reports

CARB has established a voluntary online reporting platform to facilitate initial disclosures. Companies can use the platform to submit emissions information and relevant contact details or submit their reports by email to climatedisclosure@arb.ca.gov.

The initial regulation also allows qualifying corporate groups to submit consolidated reports through a parent company, reducing the need for separate submissions from covered subsidiaries. Companies should review the applicable reporting guidance before relying on these options, particularly when determining reporting boundaries and the fiscal year covered by their disclosures.

What Businesses Should Prioritize Now

With the November deadline approaching, companies should focus on confirming their regulatory exposure and completing the first reporting cycle.

Key priorities include:

1. Confirm applicability: Review annual revenue, California business activities, relevant exemptions, and the legal entities potentially subject to SB 253.

2. Review existing emissions data: Determine whether Scope 1 and Scope 2 data is available and whether the company qualifies for CARB's first-year reporting accommodations.

3. Finalize reporting arrangements: Identify the appropriate reporting entity, determine whether consolidated reporting is available, and prepare the required submission.

4. Prepare for future requirements: Begin assessing Scope 3 emissions data, verification processes, and additional reporting obligations expected to apply from 2027.

Companies should also continue monitoring litigation concerning SB 253 and SB 261, as well as additional regulatory guidance from CARB.

Looking Ahead

California's final approval of its initial climate disclosure regulation marks a significant development in U.S. corporate sustainability reporting. Although the state has provided accommodations for the first reporting year, the November 10, 2026 deadline is now formally established for companies subject to SB 253. Organizations should not assume that ongoing litigation or first-year regulatory flexibility eliminates their compliance obligations.

As California develops its reporting framework for subsequent years, businesses will need to strengthen their emissions data collection, internal controls, and regulatory monitoring processes to support continued compliance.