The California Air Resources Board (CARB) approved the initial regulation under the Climate Corporate Data Accountability Act [Senate Bill (SB) 253] on February 26, 2026. The approval was shortly followed by a workshop in March, a reporting deadline delay in June, a public workshop held on Tuesday, July 21, 2026, and, most recently, a Notice of Public Availability of Modified Text on July 27, 2026.
Initial Regulation Updates
As announced in the June notice, CARB has withdrawn the ‘Final Package’ submitted to the Office of Administrative Law (OAL) to make clarifying changes in the rule package. CARB released the revised regulatory package in a July 27, 2026 Notice of Public Availability of Modified Text, which is subject to a 15-day public comment period with a deadline for public comment of August 11, 2026. Key changes proposed in the updated notice, mainly around clarifications to terms and definitions, are as follows:
- General wording alignment updates consistent with existing sections of the California Health and Safety Code (HSC) and California Code of Regulations (CCR).
- Clarifications around the definition of “doing business in California” by replacing the term “taxpayer” with “business entity” to clarify that doing business in California should be evaluated on an individual business entity level.
- Clarifications around the definition of “revenue” to align with the HSC and to clarify that “revenue” should be evaluated on the individual business entity level.
- Updates to the definition of “subsidiary” to reference certain specific subsections of Section 95833 of Title 17 of the CCR rather than introducing ‘indicia of control’ in this regulation directly. This change is intended to clarify stakeholder confusion regarding corporate association and parent company consolidated reports.
- Updates to the payment and collection section to clarify fiscal versus calendar year fee deadline requirements and updates around “entities” consistent with defined terms.
- Reporting deadline updates to codify the three-month deadline deferral date and report requirements for the November 2026 report only.
- Grammatical/typographical updates.
CARB has extended the reporting deadline for the initial 2026 report from August to November 10, 2026. The 2026 report includes only Scope 1 and Scope 2 greenhouse gas (GHG) emissions and does not require third-party limited assurance verification. In the July workshop, CARB also confirmed that additional guidance materials will be shared by September 1, 2026, and will include guidance documents and instructional videos, as well as a voluntary online intake platform for fee contact information and GHG emissions reporting.
Workshop Summary – 2027 and Beyond Updates
The workshop began with CARB staff walking attendees through proposed regulatory updates in the rulemaking for 2027 and beyond. The most important item was CARB’s proposal to align regulatory concepts with the Greenhouse Gas Protocol (GHG-P). This change will promote interoperability with other reporting and climate disclosure programs into which companies may already be reporting. As part of this webinar, CARB proposed regulatory wording and updates to implement GHG-P requirements, implement GHG-P recommendations, and clarify proposed California regulatory language to align with other California administrative law (AL).
Proposed Regulatory Key Concepts
CARB proposed several key regulatory concepts to align with GHG-P requirements or recommendations, or California AL. The proposed text can be found in a copy of CARB’s slides, which also contain key questions on which CARB would like additional stakeholder feedback and written comments.
The proposed regulatory concepts include:
- Quantification Methods Reporting – GHG-P requirement
- Measurement Uncertainty Reporting – GHG-P recommendation
- Missing Data and Substitution Reporting – California AL alignment
- Proposed Biogenic Emissions Reporting – GHG-P requirement and California AL alignment
- Emissions Reductions or Removals Reporting – GHG-P requirement
- Primary Data Prioritization Guidance – GHG-P recommendation
- Data Exclusions Reporting – GHG-P requirement
- Methodology Change Reporting – GHG-P requirement
- Recalculation of Previous Year Data – GHG-P recommendation and California AL alignment
In addition, CARB is proposing to include regulatory language to allow reporting entities to separately disclose additional information to add context to GHG emissions disclosures above what is required. Finally, starting in 2027, CARB is proposing a reporting deadline for Scope 1, 2, and 3 GHG emissions for the preceding fiscal year (FY) to be submitted to CARB on or before November 10 of the reporting year.
Proposed Scope 2 and 3 Emissions Reporting Requirements
CARB has incorporated some GHG-P requirements in accordance with the currently published Scope 2 Guidance (which the GHG-P team is currently in the process of reviewing and will be updating over the next few years). For Scope 3 GHG emissions reporting, CARB previously considered three options on what categories would be required. As part of this public workshop, CARB clarified that upon receiving feedback from various stakeholders in verbal and written comments, it has elected to propose requiring entities to report the five most commonly reported categories (as reported to CARB through other GHG reporting programs). Starting in 2027, CARB is proposing that facilities subject to this regulation be required to report:
In accordance with the GHG-P, each Scope 3 report would include the name and number of the category being reported, a description of the activities included in the emissions inventory, quantification and accounting methods and data types used, the sum of GHG emissions on a carbon dioxide (CO2) equivalent (CO2e) basis expressed in metric tons, an explanation for excluded emissions, and percent of emissions calculated according to different methods associated with the data. Facilities would also be able to voluntarily report on the other 10 Scope 3 categories on a voluntary basis.
Assurance Requirements
CARB received positive feedback on the assurance requirements it has previously proposed and is therefore proposing the same list of assurance standards. In addition, CARB will require that a written assurance report be issued by the assurance provider and submitted with SB 253 submittals. These reports will need to identify the assurance standard applied and level of assurance provided, the Scope 1 and Scope 2 emissions covered by the engagement, the assurance provider’s conclusion, the legal name of the organization conducting the assurance engagement, and the dates of the assurance engagement. While assurance is a requirement for all reporting entities starting in 2027, companies can do a “practice run” verification this year to ease into the reporting and verification process for next year.
Insurance Company Applicability
Several comments were submitted regarding applicability to certain insurance companies and the exemptions surrounding those companies. CARB wanted to reduce burden and not require duplicate reports but identified that CDI reporting may not satisfy all SB 253 regulations for future rulemaking, including certain Scope 3 and assurance requirements. CARB further investigated the issue and is now proposing to align reports such that an insurance company that must report to the California Department of Insurance (CDI) as required under separate rulemaking is still subject to the SB 253 regulation and should the CDI report not address all CARB requirements, reporting entities would need to supplement the report with the remaining required information.
Economic Analysis Feedback and Updates
CARB received numerous comments on the initial economic analysis, expressing concerns about CARB underestimating and overestimating certain costs and/or potential benefits. CARB recognizes that costs will be highly variable across different companies subject to this regulation and is reviewing all feedback and preparing an updated economic analysis.
CARB Next Steps
CARB is working on preparing guidance by September 1, 2026 for the 2026 initial (Scope 1 and 2 non-assured) reporting. CARB has also postedregistration links for the SB 253 sector-specific listening sessions in August and September for interested parties in certain industries and categories. CARB is also seeking feedback on several key questions identified throughout its July 2026 workshop slides, and will be accepting written comments at ClimateDisclosure@arb.ca.gov or on their website.
Conclusion
ALL4 will continue to monitor these updates by CARB and recommends companies subject to this rule:
- Evaluate the quality of your data and determine if improvements are needed,
- Prepare your 2026 SB 253 report (Scope 1 and 2, no assurance required),
- Continue to gather relevant data to prepare required calculations and reports,
- Look ahead and get prepared for Scope 3 emissions calculations, and verification and assurance for reporting in 2027 and onward.
For ALL4’s summary of the February hearing and March virtual workshop, please review our previous SB 253 article supplemented by the June 2026 updates article.
ALL4 has staff experienced in preparing GHG emissions inventories and evaluating regulatory applicability. If you need help evaluating the rule, preparing your report, calculating Scope 1, 2, or 3 emissions, or if you have follow-up questions regarding the most recent SB 253 CARB workshop, please reach out to Corey Prigent at cprigent@all4inc.com.
