More than 4,000 U.S. companies now face a firm November 10, 2026 deadline to file their first greenhouse gas emissions reports under California's finalized corporate climate disclosure regulation. The California Office of Administrative Law (OAL) has approved the Corporate Greenhouse Gas Reporting and Climate-Related Financial Risk Disclosure Initial Regulation, closing the last administrative step in a rulemaking process that began when SB 253 and SB 261 were signed into law in October 2024.

The California Air Resources Board (CARB), the agency that develops and enforces the rules, marked the approval by sending a reminder letter to companies likely to fall within scope, making sure they know the obligations and the date.

What do the two laws require?

The regulation carries two distinct reporting regimes, each with its own revenue threshold.

• SB 253 requires companies with revenues above $1 billion doing business in California to report annually on direct Scope 1 and 2 emissions in the first disclosure year, with Scope 3 value chain emissions to follow in subsequent years.
• SB 261 covers U.S. companies doing business in California with revenues above $500 million. These firms must prepare a report disclosing climate-related financial risk and the measures they take to reduce and adapt to that risk.

CARB issued a preliminary list last year identifying more than 4,000 U.S. companies likely to be required to comply.

A delayed path to finalization

The road to the November date ran through one reset. CARB approved adoption of the regulations earlier this year and submitted them to the OAL with an August 10, 2026 deadline for initial greenhouse gas reporting. In June, the regulator withdrew that submission to make limited changes to the regulation, pushing the first SB 253 reporting deadline back to November.

The final rule now carries the November 10, 2026 date for the first emissions reports.

What relief does CARB offer for the first cycle?

CARB recently released guidance confirming a series of measures to ease companies into the new requirements for the 2026 reporting cycle. The relief includes:

• Allowing the use of emissions data already collected for the prior fiscal year;
• Not requiring Scope 1 and 2 data from companies that had not yet collected such data in the past;
• Accepting emissions data even without limited assurance.

Together, the measures lower the evidentiary bar for year one while leaving the underlying disclosure obligations intact for subsequent cycles.

Does the legal challenge still matter?

Yes, and it divides the two regimes. The regulations remain under challenge in court. Late last year, the U.S. Ninth Circuit Court of Appeals issued an injunction pausing implementation of SB 261 pending the outcome of an appeal. The same court denied a request to halt SB 253, leaving the emissions reporting track — the one with the November 10, 2026 deadline — free to proceed.

What does this change for compliance planning? For SB 253 filers, nothing: the deadline is now regulatory fact, and CARB's reminder letter signals active enforcement posture ahead of the date. For SB 261 filers, the injunction keeps the financial risk disclosure track suspended until the Ninth Circuit rules.

The Ninth Circuit's decision on the SB 261 appeal now stands as the milestone that determines whether both halves of California's disclosure regime reach full force.