California SB 253 Compliance & Assurance Readiness Services

California’s Climate Corporate Data Accountability Act (SB 253) applies to U.S.-organized entities that do business in California and exceed the revenue threshold, regardless of where their parent is headquartered. For Asian groups with a U.S. subsidiary, the obligation can follow a different timeline from the group’s own climate roadmap, and it comes with a level of data rigor and third-party assurance that most home-market reporting was never designed to meet.

RESET Carbon helps enterprises answer three practical questions: what exactly applies to our U.S. entities, how far is our current data from what California expects, and what do we need to fix before an assurance provider looks at it. We combine hands-on GHG inventory expertise across Asian manufacturing and corporate operations with a clear understanding of CARB’s requirements, so your teams in Asia and the U.S. can report once, defensibly.

SB 253: Why It Matters Now

SB 253 requires covered entities to report Scope 1 and Scope 2 emissions annually from 2026 and Scope 3 emissions from 2027, with independent third-party assurance phased in over time. CARB is finalizing the rules in stages: the first Scope 1 and 2 reports are due on 10 November 2026 under transitional enforcement flexibility, while a separate rulemaking for 2027 and beyond, expected to align methodologies with the GHG Protocol and require limited assurance on Scope 1 and 2, is still being developed.

For Asia-headquartered groups, this creates a specific set of challenges. Applicability is assessed entity by entity, not at the level of the parent. Source data often sits in group systems, in local languages, and under home-market methodologies that differ from the GHG Protocol. CARB has indicated that a parent may submit a consolidated report on behalf of in-scope U.S. subsidiaries, but that report must still meet California’s requirements, and fees are assessed per entity. And because assurance is coming, the quality of the evidence trail matters as much as the number itself.

RESET Carbon bridges the gap between Asian group data and U.S. regulatory expectations, so compliance is proportionate, defensible, and built to last as the rules evolve.

When SB 253 Support is Most Relevant

Our SB 253 services are particularly relevant for organizations that:

• Are headquartered in Asia and operate a U.S. subsidiary or California operations that may trigger SB 253 obligations, and are unsure how applicability works for their legal-entity structure
• Have a group GHG inventory prepared under home-market regimes or voluntary programs, but have not tested it against the GHG Protocol and CARB requirements
• Need to decide whether a parent-level consolidated report can serve their in-scope U.S. entities
• Expect to face third-party limited assurance and want to identify evidence and control gaps before the first verification
• Treat SB 253 as a compliance requirement rather than a climate strategy project, and need a lean, proportionate way to meet it

Key Dates

• 10 November 2026: First SB 253 reports (Scope 1 and 2) due under CARB’s modified initial regulation, pending final approval. Limited assurance is not required for this cycle, and CARB’s enforcement notice allows good-faith reporting based on data entities already held or were collecting

• 2027 and beyond (proposed): Annual 10 November deadline; methodologies aligned with the GHG Protocol; Scope 3 reporting limited initially to five categories (purchased goods and services, fuel and energy-related activities, waste, business travel, employee commuting); limited assurance on Scope 1 and 2. These are preliminary CARB staff proposals to be finalized through a separate rulemaking

• 2030: Reasonable assurance for Scope 1 and 2 under the statutory timeline

Our SB 253 Readiness Services

RESET Carbon provides modular support so companies can engage at the depth their readiness and timeline require, from a focused gap analysis to a fully assurance-ready inventory.