Form FTB 3544, California Reconciliation of Worldwide and California Income, is used to reconcile the taxpayer's federal taxable income with their California taxable income. It is required to be attached to Form 100, California Corporation Franchise or Income Tax Return, if the taxpayer has a difference between their federal taxable income and their California taxable income. Form FTB 3544 is used to calculate and report the difference, which may be due to differences in the treatment of certain items for federal and state tax purposes. The form should be completed and attached to Form 100 when the taxpayer files their annual California corporate income tax return.