Combined Reporting Amendment Act of 2026

This bill updates the District of Columbia's corporate tax rules by switching from the Joyce method to the Finnigan method for calculating how much income from a group of related companies should be taxed in the city. The change directly affects businesses that operate as a single unit across multiple locations, requiring them to file a combined tax return and share joint liability for the tax owed. Key provisions redefine how a "unitary business" is identified and establish new rules for selecting which company in the group will file the return and how income is apportioned. Additionally, the legislation clarifies definitions for terms like "tax haven" and "nexus" to ensure the tax code accurately reflects modern business structures.