SB 253 First Cycle Reporting Guide: What to Prepare for 2026
CARB’s September 2026 first-year guidance describes how covered entities can approach the initial SB 253 Scope 1 and Scope 2 reporting cycle. It identifies 10 November 2026 as the expected reporting date and explains how existing emissions data, reporting formats and a statement of non-reporting fit into the first cycle. The revised regulation was still awaiting approval by California’s Office of Administrative Law when CARB issued the guidance, so confirm the current date and instructions before acting. This guide explains the reporting workflow; it does not determine whether a company is legally in scope.
Official sources
Last reviewed: 16 September 2026
Recheck CARB’s 2026 SB 253 Reporting Guidance, the corporate greenhouse gas reporting program page and the December 2024 enforcement notice before you set a filing calendar. Do not treat a date from this page as a confirmed final deadline if CARB’s live instructions have changed.
Start with the first cycle decision
The first reporting cycle is unusual. CARB’s guidance says covered entities should use Scope 1 and Scope 2 information that was in their possession or being collected as of 5 December 2024. An entity that was not collecting, and was not planning to collect, that information by that date may use a statement of non-reporting under CARB’s guidance rather than create emissions data for this first submission. The statement does not decide whether the law applies to the entity; it communicates the entity’s first-cycle reporting position under the guidance.
This distinction matters for teams sorting through old spreadsheets, energy reports, fuel records and earlier disclosures. First establish which reporting path appears relevant, then organise the records and explanations that support it. If you are unsure whether the law covers your organisation, start with GreenKPO’s applicability guide to screen SB 253 applicability factors and obtain legal advice for the final determination.
1. Confirm the entity and reporting boundary
Before assembling a report, identify the entity or parent organisation that will report, the fiscal year represented and the facilities or operations included in the boundary. Record the basis for parent and subsidiary treatment, any exclusions considered and who approved the boundary. Where multiple entities or business units contribute information, keep the source records associated with the reporting unit they support.
Revenue, California business activity, entity structure and exclusions can affect applicability. A revenue threshold alone is not a final coverage decision. Use the applicability guide to organise the screening information, then have the appropriate legal or compliance adviser confirm the conclusion.
2. Identify what existed by 5 December 2024
List the Scope 1 and Scope 2 information the organisation possessed or was collecting by the date stated in CARB’s enforcement notice. For each item, note the reporting period, source, owner, location or facility, unit, method and any estimate used. Examples may include existing emissions inventories, energy data, fuel records or information already prepared for another reporting programme. Do not treat this list as a universal set of required sources; the relevant information depends on the organisation and its operations.
If the organisation was not collecting or planning to collect Scope 1 and Scope 2 data by that date, CARB’s guidance describes a statement of non-reporting for the 2026 cycle. Follow CARB’s current wording and submission instructions. Keep the approved statement, the decision record and the evidence used to support that position together.
3. Select an accepted reporting format
CARB’s 2026 guidance describes several ways to provide first-cycle emissions information, including an existing annual report, Scope 1 and Scope 2 data already reported through another programme or voluntary initiative, or CARB’s reporting template. Check the current guidance for the applicable format and required submission details. Do not assume that a GreenKPO report or another existing document can be submitted unchanged; confirm that it contains the information CARB currently requests.
CARB also describes a voluntary reporting intake platform for first-cycle submissions. The platform can be used to provide contact and billing information and, where applicable, emissions data. Check CARB’s live instructions for the current submission route, required fields and any fees. Keep a copy of the submitted material and any receipt or confirmation with the reporting record.
4. Make the figures understandable to reviewers
A total is easier to review when its source and calculation are visible. Where available, keep a concise record of the reporting boundary, data source, calculation method, emission factors, global warming potential values, assumptions, units, estimates and material changes. CARB’s guidance encourages additional context where available, including data sources, methodologies, boundaries and disaggregated emissions information. Follow the guidance to distinguish requested information from details that are encouraged or optional.
For each figure, retain the record used to support it and note who checked the calculation. Record unresolved gaps or limitations plainly. If the same source has been converted, allocated or estimated, preserve the original input and explain the adjustment. This helps finance, facilities and sustainability teams answer questions without rebuilding the reporting trail later.
5. Check the assurance position and current instructions
CARB’s September 2026 guidance says it will accept first-cycle submissions whether or not limited assurance has been obtained. Treat that as a statement about the 2026 submission approach described in the guidance, not as a general exemption from assurance requirements in later reporting years. Recheck CARB’s current instructions and the applicable regulation before submission, especially if the regulatory status or reporting date has changed.
How GreenKPO can support the preparation work
GreenKPO’s role is to help teams organise emissions data and supporting records for review. If you need to bring source information together, see the data-collection software workflow. For a detailed list of reporting-readiness tasks and evidence to assemble, use the SB 253 reporting readiness checklist. The SB 253 software page explains the reporting workflow and current platform capabilities.
GreenKPO does not make the legal applicability decision, provide legal advice or replace CARB’s submission instructions. Confirm that any platform feature or service described on the linked pages is available before relying on it for a reporting task.
Common questions
Is 10 November 2026 the final reporting date?
CARB’s September 2026 guidance identifies 10 November 2026 for the first cycle, while the revised regulation was still awaiting approval at the time. Confirm the date and submission instructions on CARB’s current programme page before filing.
Does an organisation without existing data need to create a new inventory for this cycle?
CARB’s guidance describes a statement of non-reporting for entities that were not collecting and were not planning to collect Scope 1 and Scope 2 data by 5 December 2024. Follow the current CARB guidance and check the organisation’s reporting position with its advisers.
Is this guide a substitute for the SB 253 checklist?
No. This guide explains first-cycle reporting paths and context. The SB 253 reporting readiness checklist covers the step-by-step readiness inventory, controls and evidence tasks.
Does GreenKPO decide whether SB 253 applies?
No. The applicability guide helps organise screening information. It does not determine the legal obligation or replace legal advice.
Discuss your first-cycle reporting data readiness
Bring your entity boundary, available Scope 1 and Scope 2 records and first-cycle reporting path. We can help organise the information and identify data gaps for your finance team and legal advisers to review.