California Conformity to Federal Law
In general, California tax law conforms to the Internal Revenue Code (IRC) with modification. However, there are differences between California and federal tax law. Certain specific areas of conformity and nonconformity are discussed in the affected tax forms instructions and in our Supplemental Guidelines to California Adjustments (Publication 1001).
On September 30, 2015, Assembly Bill 154, the Conformity Act of 2015 was enacted. The Act changed California’s specified date of conformity to the IRC from January 1, 2009, to January 1, 2015.