California's SB 253 sets the first Scope 1 and 2 deadline for August 2026

California’s CARB just locked in SB 253: first Scope 1+2 reports are due 10 August 2026, Scope 3 follows in 2027 for large entities doing business in the state

Many will feel the data gap immediately. Insetting can turn that compliance pressure into funded, verifiable reductions shared across suppliersThis is what C3’s marketplace was built for. Worth exploring if your value chain touches California: https://carbon3.net

The staggered timetable gives companies a year between the first disclosure and the Scope 3 requirement, and most will use it to discover how little of their value-chain data they actually hold. The rule does not require reductions, but it will make the size of the Scope 3 problem visible to regulators, investors and customers at the same time.

Visibility is where the commercial pressure starts. Once the number is public, the question becomes what the company is doing about it, and insetting is one of the few answers that produces a verifiable reduction inside the reported boundary rather than a purchased claim from outside it.