The Alaska corporate income tax return (Form 04-611) must be filed within thirty days of the deadline for the corporation’s federal income tax return. Therefore, the due date for the Alaska return may not necessarily fall on the fifteenth day of the month following the federal deadline.

Corporations that request a federal income tax extension are automatically granted an Alaska tax extension, which extends the state filing dead line to thirty days after the (extended) federal filing due date. Thus, if you have successfully requested a federal tax extension, there is nothing more you need to do ― just make sure to attach a copy of your federal tax extension to your Alaska tax return.

Note that a tax extension is an extension of time to file your return, not an extension of time to pay the tax that you owe. Full payment of your Alaska tax must still be made by the original due date of your return (typically the fifteenth day of the third month following the close of the tax year). Tax payments can be made by Electronic Funds Transfer (EFT), wire transfer, or check.

For additional information, please visit the Alaska Department of Revenue "Tax Division" website.