CaliforniaSB253complianceguide2026:whattoreportandbywhen

California’s Senate Bill 253, the Climate Corporate Data Accountability Act, is now in force. It requires U.S. companies with more than $1 billion in annual revenue that do business in California to publicly disclose their greenhouse gas emissions. This is not a voluntary framework: it is a binding law enforced by the California Air Resources Board (CARB), with administrative penalties of up to $500,000 per reporting year. The first Scope 1 and 2 reports are due in 2026, with the deadline recently moved to November 10, 2026.

What you’ll find in this guide

This guide helps you know exactly where you stand and what you need to do before the deadline:

• What SB 253 is and who has to comply (the $1B revenue threshold and what “doing business in California” means)
• Exactly what you must disclose: Scope 1, 2 and 3 emissions under the GHG Protocol
• The updated timeline: Scope 1 & 2 in 2026 (deadline moved to November 10, 2026) and Scope 3 from 2027
• How third-party assurance phases in, from limited to reasonable
• How SB 253 relates to SB 261 (climate-related financial risk) and whether you are caught by both
• Why compliance is, at its core, an emissions-data challenge
• A step-by-step roadmap to get audit-ready in time

Download the full guide

Most of the work in SB 253 is not the reporting form: it is getting clean, traceable emissions data across your operations and value chain. The companies that comply without last-minute stress are the ones whose Scope 1, 2 and 3 numbers are connected to their real source and ready for assurance. This guide shows you how to get there before the CARB deadline, without a five-figure consulting invoice.