
State Corporate Income Tax Apportionment in 2026: How Single Sales Factor and Market-Based Sourcing Reshape SaaS Tax Bills
A guide to state corporate income tax apportionment in 2026 — why 34 of 44 corporate-tax states now use single sales factor, how market-based sourcing rules in California, Kansas, and Arkansas shift SaaS and service company tax bills toward customer location, and five strategies to manage the exposure.










