SB 253 Rulemaking Completion and CARB's Reset of the Reporting Deadline

Overview

The California Air Resources Board (CARB) advanced its rulemaking for the greenhouse gas emissions reporting regulations under SB 253 during 2026, completing an initial rulemaking that reset the previously anticipated reporting deadline. In the district court proceedings, plaintiffs (including the U.S. Chamber of Commerce) had raised claims that the law violated the dormant commerce clause and the federal Supremacy Clause; both claims have already been dismissed. As a result, the sole issue now being litigated on appeal (before the Ninth Circuit, in Chamber of Commerce v. Sanchez) is narrowly limited to whether mandating corporate emissions disclosure violates the First Amendment's prohibition on compelled speech.

Oral arguments were held on January 9, 2026, but as of August 2026, a ruling remains pending. CARB has repeatedly stated that, even while the rulemaking process was ongoing, the SB 253 reporting obligation itself remained legally valid and that the compliance deadline was unchanged. Covered companies (those doing business in California with total global annual revenues exceeding $1 billion) need to prepare on the premise of an annual disclosure obligation for Scope 1 and 2 emissions beginning in 2026, and for Scope 3 emissions beginning in 2027.

Enforcement Timeline

2026: CARB completes its initial rulemaking for SB 253 and resets the reporting deadline

January 9, 2026: Oral arguments held before the Ninth Circuit Court of Appeals (Chamber of Commerce v. Sanchez)

As of August 2026: The appellate ruling remains pending; CARB maintains that the SB 253 reporting obligation is legally valid and the compliance deadline is unchanged

Business Impact

Companies subject to SB 253 should proceed with compliance preparation on the assumption that the reporting obligation remains fully in force, since the rulemaking has been finalized and the underlying legal challenges no longer include the broader constitutional claims (dormant commerce clause, Supremacy Clause) that had originally been raised. Only the narrower First Amendment compelled-speech question remains before the Ninth Circuit, and companies should treat the outcome of that appeal as the primary source of remaining legal uncertainty, rather than assuming the reporting deadline itself is at risk.