The California Office of Administrative Law (OAL) has approved the California Corporate Greenhouse Gas Reporting and Climate-Related Financial Risk Disclosure Initial Regulation, marking the final step in the adoption of the new climate reporting regulation for thousands of large U.S. companies, and officially establishing November 10, 2026 as the deadline for the first greenhouse gas emissions reports.

Alongside the OAL approval, the California Air Resources Board (CARB), the regulator charged with developing and enforcing the state’s new corporate climate reporting regulations, announced that it has sent a reminder letter to companies that may be in the scope of the new requirements to ensure that they are aware of the new reporting obligations and deadline.

California’s new climate reporting regulations, SB 253 and SB 261, were signed into law in October 2024. SB 253 will require companies with revenues greater than $1 billion that do business in California to report annually on their direct Scope 1 and 2 emissions in the first year of disclosure, and to add Scope 3 value chain emissions disclosure beginning in subsequent years. SB 261 requires U.S. companies that do business in California and with revenues greater than $500 million to prepare a report disclosing their climate-related financial risk, as well as measures to reduce and adapt to that risk.

Notably, the regulations are still facing legal challenges, with the U.S. Ninth Circuit appeals court issuing an injunction late last year to pause the implementation of SB 261 pending the outcome of an appeal, but denying a request to halt SB 253.

The new laws apply to many large companies in the U.S., with CARB issuing a preliminary list last year of more than 4,000 U.S. companies likely to be required to comply with the new climate reporting requirements.

CARB approved the adoption of the regulations earlier this year, and submitted the regulations for final approval by the OAL, with a deadline of August 10, 2026 for initial reporting of corporate greenhouse gas (GHG) emissions. The regulator, however, announced in June that it had withdrawn the submission to make limited changes to the regulation, delaying the deadline for initial reporting under SB 253 to November.

CARB also recently released new guidance which confirmed a series of measures to ease the transition into the new emissions reporting requirements, including 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 the data in the past, and accepting emissions data even without limited assurance, for the 2026 reporting cycle.

Click here to access CARB’s reminder letter to companies.