Due dates for filing income and franchise tax returns, paying estimated income and franchise tax installment payments, and filing withholding tax returns. (FE)

1. For taxable years beginning after December 31, 2015, for a partnership, limited liability company, or tax-option corporation, March 15 or the 15th day of the third month following the close of the entity's fiscal year.

2. For taxable years beginning after December 31, 2015, for a corporation other than a tax-option corporation, except for a corporation that has a taxable year ending on June 30, April 15 or the 15th day of the fourth month following the close of the corporation's fiscal year.

3. For taxable years beginning after December 31, 2015, and ending before January 1, 2024, for a corporation, other than a tax-option corporation, that has a taxable year ending on June 30, the 15th day of the third month following the close of the corporation's fiscal year.

4. For taxable years beginning after December 31, 2025, for a corporation, other than a tax-option corporation, that has a taxable year ending on June 30, the 15th day of the fourth month following the close of the corporation's fiscal year.

The bill amends the due dates under Wisconsin law for those entities to file state income and franchise tax returns to conform to the federal income tax return filing due dates.

The bill also provides that a corporation that is required to pay periodic installments of estimated Wisconsin income or franchise tax must pay the first installment of the tax on or before the 15th day of the fourth month of the corporation's taxable year, except that, if the corporation's taxable year ends in March, the first installment must be paid in the third month of the corporation's taxable year. Under current law, the first installment for all corporations is due on the 15th day of the third month of the corporation's taxable year.

The bill also changes the due date for a partnership, limited liability company, tax-option corporation, estate, or trust (pass-through entity) to file a withholding tax return for amounts withheld from income of the pass-through entity that are distributable to a nonresident partner, member, shareholder, or beneficiary. The bill changes that due date to be the same as the due date for the pass-through entity to file its federal income tax return.

Under current law, if a pass-through entity underpays estimated withholding tax, the pass-through entity must pay interest on the amount of the underpayment for the period of the underpayment. The bill provides that no interest must be paid if the secretary of revenue determines that because of casualty, disaster, or other unusual circumstances it is not equitable to impose interest.