In this article, we explore must comply and its importance for corporate sustainability management.
Your company already generates environmental data through energy bills, fuel records, purchasing transactions and supplier information. Those records can support California’s SB 253 requirements while also helping finance and operations teams understand costs, resource consumption and business risks.
The difficulty is often repeated collection. Teams prepare an emissions inventory, reorganise it for a customer questionnaire and request the same evidence again for an external review. Separate files create unnecessary work and make differences between figures harder to explain.
Dcycle structures that information once so it can serve several purposes. Compliance becomes one output, alongside savings analysis, supplier evaluation and operational decisions.
California’s SB 253, the Climate Corporate Data Accountability Act, creates emissions disclosure obligations for covered U.S. business entities doing business in the state. It reaches beyond companies headquartered in California and includes public and private businesses.
The first deadline is now confirmed. CARB’s October 12 approval notice states that the initial regulation took effect that day and sets November 10, 2026 as the emissions submission deadline. The deferral is no longer awaiting Office of Administrative Law approval.
Companies need to establish whether they are covered, identify the appropriate inventory boundary and apply the relevant first-cycle provisions. They should also prepare a process that remains useful as Scope 3 and later requirements develop.
The first reporting cycle is already underway. CARB adopted an initial regulation for SB 253 in February 2026 and set August 10, 2026 as the first-year deadline. CARB's current program page says it is updating the regulation to defer that deadline to November 10, 2026, subject to approval by the Office of Administrative Law. Companies should confirm the final status directly with CARB before filing.
This article explains who must comply, what the law requires, how the current implementation timeline works, what assurance means in practice, and how companies can build a reusable emissions data process.
What SB 253 requires
What SB 253 requires
SB 253 requires covered companies to disclose greenhouse gas emissions through California’s implementation programme.
The inventory needs an appropriate organisational boundary, calculation methods and supporting records. It is not simply a total of emissions generated within California.
The law’s accounting basis includes the GHG Protocol Corporate Standard. Companies should maintain consistent definitions and document how activity records become emissions results.
The three emissions scopes cover different activities and require different sources.
Scope 1 emissions from owned or controlled sources
Scope 1 emissions from owned or controlled sources
Scope 1 includes direct emissions from sources owned or controlled by the company under the applicable organisational approach.
Examples include:
- Fuel combustion in boilers, furnaces and generators.
- Fuel used by vehicles within the inventory boundary.
- Industrial process emissions.
- Refrigerant leaks and other fugitive emissions. A fleet’s fuel records may provide part of the calculation, but companies should distinguish purchases from consumption where this affects the period being measured.
Facility and maintenance teams may hold information that does not appear in the accounting system. Refrigerant additions, equipment servicing and process measurements therefore need appropriate owners.
These records also support operational decisions. Fuel consumption can inform fleet reviews, while process information can help identify resource-intensive activities.
Scope 2 emissions from purchased energy
Scope 2 emissions from purchased energy
Scope 2 covers emissions associated with purchased electricity, steam, heat and cooling consumed by the organisation.
Companies need to identify the relevant utility accounts, facilities, contracts and periods. They should also retain the factors and contractual evidence used in the calculation.
Where applicable, dual Scope 2 calculations distinguish location-based and market-based results. These perspectives should not be blended into a single unexplained figure.
The same electricity records can support emissions calculations and expenditure reviews. However, a lower market-based result does not necessarily mean the company consumed less electricity or reduced its energy costs.
Review consumption, procurement arrangements and expenditure separately before drawing an operational conclusion.
Scope 3 emissions across the value chain
Scope 3 emissions across the value chain
Scope 3 covers other indirect emissions associated with upstream and downstream activities.
The GHG Protocol identifies 15 categories, including purchased goods and services, capital goods, transport, waste, business travel, employee commuting, use of sold products and end-of-life treatment.
This part of the inventory often requires procurement, logistics, product and supplier information. The appropriate calculation method depends on the category and available records.
Supplier-specific information can improve an estimate, but it still needs review. A supplier’s corporate footprint is not automatically the footprint of the goods purchased from that supplier.
A comparison of Scope 3 software should therefore examine category coverage, source quality and methodology visibility. Automated collection is useful only when teams can understand what the inputs represent.
Define boundaries and methods before sending large numbers of questionnaires. Otherwise, companies can collect substantial volumes of information that do not answer the calculation question.
Who is in scope?
Who is in scope?
The core statutory test concerns covered U.S. business entities with annual revenues above $1 billion that do business in California.
The company does not need to be incorporated or headquartered in California. A business formed in another U.S. state may be covered.
CARB’s initial regulation announcement explains that the programme applies to public and private companies and identifies categories of exempt entities. These include specified nonprofit, government and insurance entities, among other exclusions.
Companies should assess the current definitions rather than relying on their public listing status or a general description of their industry.
Revenue and California activity need separate checks
Revenue and California activity need separate checks
Do not assume that the $1 billion threshold means $1 billion of California sales.
The revenue calculation and the test for doing business in California are separate parts of the assessment. Both need to follow the applicable definitions.
Likewise, a customer relationship or employee location should not be treated as a complete legal analysis. Document the relevant business activity and any applicable exclusions.
The result should identify which entity is covered and the basis for that conclusion.
Groups need a documented entity review
Groups need a documented entity review
A group should map its U.S. entities, ownership, revenue and California activities.
A foreign parent does not automatically make every U.S. subsidiary exempt. Conversely, group membership alone does not establish that each subsidiary has an individual filing obligation.
Separate the legal coverage assessment from the organisational boundary used to calculate emissions. Then determine how the applicable consolidation and submission arrangements work.
A written scope memorandum helps legal, finance and environmental teams avoid working from different assumptions.
SB 253 is different from SB 261
SB 253 is different from SB 261
SB 253 concerns greenhouse gas emissions.
SB 261 concerns climate-related financial risk and has a different threshold, disclosure structure and implementation history.
Do not transfer a deadline, exemption or court-related development from one programme to the other without checking its application.
For companies managing both, the information processes may overlap, but the legal assessments remain distinct.
Key deadlines and implementation phases
Key deadlines and implementation phases
The original August 10, 2026 date has been replaced by November 10, 2026 under the approved initial regulation.
CARB’s October notice also confirms that the first disclosures cover Scope 1 and Scope 2, with Scope 3 included in subsequent years beginning in 2027.
| Phase | Information covered | Preparation focus |
|---|---|---|
| November 10, 2026 deadline | Initial Scope 1 and Scope 2 submission | Confirm applicability, relevant fiscal-year information and available first-cycle provisions |
| Reporting beginning in 2027 | Scope 3 joins the programme | Prepare category screening, supplier information and documented estimates |
| Subsequent cycles | Recurring emissions disclosures and developing implementation requirements | Maintain methods, evidence, controls and an updated regulatory calendar |
The applicable fiscal-year treatment should be checked against CARB’s instructions. Do not assume that every company must use the same calendar-year dataset.
First-cycle flexibility is not a permanent exemption
First-cycle flexibility is not a permanent exemption
CARB has described flexibility for the initial submission, including optional use of its template and acceptance of submissions without limited assurance. Its first-cycle implementation materials distinguish these arrangements from the programme’s longer-term requirements.
Companies should assess whether any available first-cycle relief applies to their circumstances. It is not permission to select an incomplete approach without documenting the basis.
The statutory assurance model and CARB’s initial submission position should also be kept separate. Administrative flexibility for the first cycle does not remove the need to prepare for later requirements.
Submission arrangements should be confirmed
Submission arrangements should be confirmed
CARB’s October notice identifies a voluntary intake platform and an email submission route.
The availability of a platform does not make that platform mandatory. Companies should follow the current instructions, retain what was submitted and preserve confirmation of the chosen delivery method.
Assign responsibility for the final submission. Calculation teams, reviewers and the person authorised to transmit the information may have different roles.
Scope 3 preparation should already be underway
Scope 3 preparation should already be underway
The first Scope 1 and Scope 2 deadline should not absorb all planning capacity.
Scope 3 work may require supplier engagement, product assumptions and records from departments that were not involved in the initial inventory.
Start with category screening and existing information. Then prioritise gaps rather than issuing an identical request to every supplier.
The 2027 filing details should be checked as CARB completes further rulemaking. Avoid assigning an unverified date simply because the first-cycle deadline is known.
The most reliable approach is to monitor CARB's reporting program and regulatory materials, document which deadline applies to the company's fiscal year, and maintain an internal calendar that allows time for calculation, review and submission.
Assurance requirements
Assurance requirements and audit readiness
Assurance examines information against defined criteria and an agreed scope.
It is not a guarantee that every record is error-free, and it does not replace management responsibility for the inventory.
Companies should distinguish the statutory assurance framework, the first-cycle administrative position and the detailed procedures applicable to later periods.
Limited and reasonable assurance
Limited and reasonable assurance
Limited assurance involves less extensive procedures than reasonable assurance and provides a lower level of assurance.
The conclusion is generally expressed in negative form, addressing whether anything came to the practitioner’s attention indicating a material misstatement.
Reasonable assurance involves more extensive procedures and a positive-form conclusion. It still does not provide absolute certainty.
When planning future engagements, confirm the applicable period, scope, assurance level and provider requirements. Do not assume that the initial 2026 submission arrangements continue unchanged.
Evidence should accompany the calculation
Evidence should accompany the calculation
Each relevant figure should be connected to:
- Its original source.
- The reporting entity, facility and period.
- The organisational boundary.
- The factor and conversion used.
- The calculation method.
- Preparation and approval responsibilities.
- Estimates, exclusions and changes. A carbon footprint audit examines this chain of information, not only the final emissions total. Preparing the records during collection makes the result easier to review.
For example, a fuel total needs more than an invoice attachment. The reviewer must understand which vehicles it covers, whether the quantity belongs to the relevant period and how it was converted into emissions.
Test the evidence trail internally
Test the evidence trail internally
Select several results and trace them backwards to the source.
Include a straightforward utility record, an estimated activity and a corrected figure. This tests whether the process handles more than the ideal case.
Ask someone other than the original preparer to reconstruct the calculation. If the explanation depends on personal memory, additional documentation is needed.
These checks also help operations and finance investigate unexpected changes before publication.
This documentation should be created during data collection. Reconstructing it after the inventory is complete creates avoidable delays and makes it harder to explain inconsistencies. Evidence and traceability workflows help keep source files, calculations, owners and approvals connected to the reported result.
Penalties and business consequences
Penalties and business consequences
SB 253 includes an administrative enforcement framework. Companies should check the current statute, regulation and enforcement materials rather than treating exposure as a fixed, automatic fine.
The consequences can depend on the failure involved, the applicable period and the relevant provisions. A late submission, an unsupported figure and an error identified during review should not be assumed to receive identical treatment.
First-cycle flexibility should not be interpreted as a general absence of responsibility.
Commercial consequences also need context. Customers, lenders and investors may compare emissions information with other disclosures and representations.
An unexplained inconsistency can create additional questions, but it does not automatically mean a company will lose financing or a contract.
The practical objective is a repeatable process that produces information the company can explain, correct and reuse.
SB 253 and CSRD share data, not identical requirements
SB 253 and CSRD share data, not identical requirements
SB 253 focuses on greenhouse gas emissions under California’s programme.
CSRD operates within a broader framework that can include environmental, workforce, governance and other information, together with double materiality and applicable assurance requirements.
The relationship between CSRD and ESRS illustrates why framework names should not be treated as interchangeable. Each requirement needs its own scope and criteria.
Companies already preparing European disclosures may be able to reuse source records, calculation methods and controls. That can reduce repeated collection, but it does not establish automatic SB 253 compliance.
Check boundaries before reusing results
Check boundaries before reusing results
A European group inventory may include entities that differ from the relevant California submission boundary.
Periods, consolidation approaches, acquisitions and exclusions can also affect the comparison.
Map these differences explicitly before transferring totals. Reusing source records is often more reliable than copying a published number without understanding its construction.
Keep methods and evidence consistent
Keep methods and evidence consistent
Document factors, assumptions and changes so that differences between outputs can be explained.
The same electricity record can contribute to several disclosures and internal analyses. The resulting emissions total may still depend on the applicable boundary and method.
A common evidence base reduces duplication while allowing each output to retain its own requirements.
Preserve non-disclosure uses
Preserve non-disclosure uses
Energy, fuel and purchasing records remain useful after a submission is completed.
Finance can assess expenditure, procurement can evaluate supplier information and operations can investigate consumption trends.
A shared process supports these decisions without requiring SB 253 to become the only reason environmental data is maintained.
How Dcycle connects SB 253 preparation with operational data
How Dcycle connects SB 253 preparation with operational data
Dcycle is a data platform for companies managing emissions information across entities, facilities, business units and suppliers.
It structures activity records, calculations and supporting evidence so teams can maintain a repeatable process.
When evaluating carbon accounting software, companies should test that complete path. The relevant question is whether the platform can work with their sources and controls, not simply whether SB 253 appears on a framework list.
Dcycle does not determine legal applicability or replace independent assurance. It supports the information process that companies need for those assessments and reviews.
Centralised Scope 1 and Scope 2 information
Centralised Scope 1 and Scope 2 information
Dcycle supports collection through compatible integrations, uploaded documents and structured templates.
Utility, fuel, facility and fleet records can be organised by entity, location, period and activity.
This helps contributors work from shared sources rather than maintaining separate files for every output.
The implementation should confirm collection frequency, integration scope and responsibility for resolving exceptions.
Scope 3 information across the value chain
Scope 3 information across the value chain
The platform supports the 15 GHG Protocol Scope 3 categories and different calculation paths according to the available information.
Teams can distinguish supplier-specific records from activity-based or spend-based estimates.
That distinction helps identify which results need better information and which supplier requests should be prioritised.
A supplier response still requires review. Receiving primary information does not automatically establish that its boundary, allocation or methodology is suitable.
Traceability and review preparation
Traceability and review preparation
Source records can remain connected to factors, calculations and processing history.
This helps teams explain results and investigate changes before they become late-stage review issues.
Roles and approval workflows support accountability, while evidence organisation makes information easier to retrieve.
Assurance readiness is an ongoing process. The platform can support it, but it cannot guarantee a particular assurance conclusion.
One source record with several uses
One source record with several uses
Consider a fuel record for a vehicle fleet.
It can contribute to the Scope 1 inventory, a fuel-cost review and an operational efficiency analysis. The latter also requires information such as distance travelled, vehicle type and operating conditions.
Dcycle keeps the underlying information structured so each team does not need to enter the same record independently.
If the source is corrected, the company can assess the affected calculations and decide which outputs need another review.
Multiple frameworks without assuming equivalence
Multiple frameworks without assuming equivalence
Shared records can support SB 253 preparation, European climate disclosures, CDP responses and customer requests.
The mapping must preserve differences in boundaries, methods and periods. Some requirements may need additional information.
When a framework changes, teams can review the affected calculations and outputs while retaining the original source records.
Compliance is therefore one use of the data. Savings analysis, supplier evaluation and operational decisions can continue throughout the year.
5 Actions companies should take now
5 Actions companies should take now
1. Confirm the entity and inventory boundary
- Confirm the entity and inventory boundary
Identify the relevant U.S. entities and assess revenue and California activity using the applicable rules.
Review ownership, consolidation and exemptions. Record the conclusion and the information supporting it.
Then define the facilities and activities included in the emissions inventory. The legal coverage assessment and calculation boundary should be consistent, but they are not the same task.
Assign an owner to maintain the scope assessment when the business changes.
2. Map Scope 1 and Scope 2 sources
- Map Scope 1 and Scope 2 sources
List facilities, fleets, fuel sources, process emissions, refrigerants, utility accounts and purchased energy.
Record the source owner, collection frequency and available evidence.
Prioritise gaps that affect the initial submission. Check units, periods and overlaps before consolidating information.
Automate stable collection where appropriate, while keeping a process for missing records and corrections.
3. Prepare Scope 3 categories and supplier engagement
- Prepare Scope 3 categories and supplier engagement
Screen the relevant upstream and downstream categories.
Identify where activity information exists, where supplier-specific information is suitable and where estimates are needed.
A structured supplier data process helps track requests and review the quality of responses. Supplier participation should be prioritised according to relevance rather than treated as a uniform exercise.
Keep the assumptions behind product-use, transport and other estimates. A documented approximation is more useful than an apparently precise result with no clear basis.
4. Agree methods, controls and approvals
- Agree methods, controls and approvals
Define factor selection, organisational boundaries, estimation rules and Scope 2 treatment.
Separate raw records from calculated metrics and approved outputs.
Establish how corrections are reviewed and which changes require recalculation. Historical figures should not change silently when a factor database or source record is updated.
The process should be rigorous enough to maintain, without becoming so complicated that contributors stop using it.
5. Connect compliance with other business uses
- Connect compliance with other business uses
Identify where the same records are needed for CDP, customers, lenders, CSRD and reduction planning.
Map each use rather than creating a new inventory for every request.
Internal intensity metrics can connect emissions or consumption with production or activity. They should be assessed alongside absolute figures so that growth and efficiency effects remain visible.
This is where environmental data becomes useful to operations and finance, not only to the disclosure team.
Conclusion
Conclusion
SB 253 requires covered companies to establish a reliable emissions process, not simply produce a total before a deadline.
For the initial cycle, November 10, 2026 is the confirmed deadline under the regulation effective October 12. Companies should check their applicability, fiscal-year treatment and available first-cycle provisions, while preparing for Scope 3 reporting beginning in 2027.
The strongest foundation combines clear boundaries, documented methods, accessible evidence and defined review responsibilities.
Existing CSRD or other disclosure processes may provide useful infrastructure, but results should be mapped carefully rather than copied without checking their scope.
Dcycle structures environmental information so the same records can support compliance, savings analysis and operational decisions. If you are assessing the platform, request a demonstration using your own energy, fuel and supplier records to test the process against your actual requirements.
If you need to assess your reporting boundary, organize your emissions data or prepare for assurance,
Request a Dcycle demoFrequently asked questions (FAQs)
Does SB 253 apply only to companies headquartered in California?
No. It applies to covered U.S. business entities with annual revenue above $1 billion that do business in California. The entity does not need to be headquartered or incorporated in California.
Does SB 253 require Scope 3 reporting?
Yes. Scope 3 reporting begins in the later phase of the program, currently associated with reporting beginning in 2027. Companies should start supplier and category-level preparation well before the first Scope 3 submission.
Does SB 253 apply to private companies?
Yes. SB 253 applies to covered public and private companies. The reporting obligation is not limited to SEC registrants.
Is limited assurance required for the initial 2026 reporting cycle?
CARB's 2026 implementation materials indicate that limited assurance is not required for the initial 2026 Scope 1 and Scope 2 cycle. Future assurance requirements are being developed through the CARB rulemaking process.
Are SB 253 and SB 261 the same law?
No. SB 253 covers greenhouse gas emissions reporting. SB 261 covers climate-related financial risk reporting and has a different revenue threshold and reporting structure.
Can companies reuse CSRD data for SB 253?
Often, yes. The frameworks have different legal scopes, but their emissions inventories, supplier processes, evidence requirements and calculation controls can overlap. The data should be mapped carefully rather than copied without reviewing boundaries and methodology.
