Amended market-based sourcing rulesTax News Flash

September 12, 2025

The Office of Administrative Law recently approved amendments to California Code of Regulations, title 18, section 25136-2, concerning market-based sourcing rules. These amendments were filed with the Secretary of State on August 27, 2025 and have an effective date of October 1, 2025.

For more information, please visit: Final regulations

Last updated: 01/02/2026