Alaska Form 6390 – Federal-Based Credits
Last reviewed: 2025-11-12
Use the Alaska Tax Form Calculator Form 6390: Alaska Form 6390 – Federal-Based Credits as a stand alone tax form calculator to quickly calculate specific amounts for your 2026 Alaska state tax return. Alternatively, you can use one of our Combined Federal and State Tax Estimators to quickly calculate your salary, tax, and take-home pay.
Alaska Form 6390 is used by corporations to compute Alaska’s allowable portion of federal-based business credits. Although these credits originate at the federal level—primarily via the general business credit system (Form 3800)—Alaska applies its own allocation, apportionment and limitation rules. Form 6390 consolidates these requirements into a structured multi-part calculation that determines how much of the federally generated credit can reduce a corporation’s Alaska income tax liability.
The form accounts for credit types that behave differently under Alaska law, including passive-activity credits, investment credits not allowed for Alaska AMT, credits flowing through from partnerships or S corporations and credits that exceed the current-year limitation. By integrating both the regular Alaska tax and the Alaska alternative minimum tax (AMT), Form 6390 ensures that corporations adopt the correct multi-layered credit restrictions before applying offsets to their return (Forms 6000, 6100 or 6150).
This calculator replicates all computational lines, allowing businesses to evaluate available credits, allowable credit limits and the amount eligible for carryback or carryforward. It is especially useful for multi-state corporations that must apply Alaska’s apportionment factor to determine the state-specific share of federal credits.
How Alaska Form 6390 Works
The structure of the form divides the credit computation into segments that progressively refine the allowable amount. The major components are:
- Identify federal-based credits: Enter general business credits from federal Form 3800, separating passive-activity and non-passive-activity amounts. These amounts then undergo Alaska-specific disallowance adjustments.
- Apply Alaska apportionment: Alaska requires all federal-based credit amounts to be multiplied by the corporation’s Alaska apportionment factor, ensuring that only Alaska-sourced business activity impacts the credit determination.
- Compute AMT interactions: Alaska distinguishes credits available against regular tax and those that also apply to Alaska AMT. The form walks through these calculations to establish both totals.
- Calculate tax limitations: The form uses several limitation tests, including a threshold for reducing credits when Alaska regular tax exceeds $4,500. These limitations prevent credits from reducing tax below permitted levels.
- Determine allowable credit and carryover: The form concludes with the credit allowed for the current year and the remaining amount eligible for carryback or carryforward. These figures feed directly into Form 6000, 6100 or 6150.
Corporations with complex federal-credit structures, such as energy credits, rehabilitation credits or investment credits, rely on Form 6390 to ensure Alaska-specific compliance. The calculator automates all arithmetic steps while still following the exact line-by-line layout of the official form.
| PART I — Current Year Credit for Credits Not Allowed Against Alaska AMT | ||
| 1 | Federal general business credit from non-passive activity (Form 3800, Part III line 2e) | |
| 2a | Federal investment credit from non-passive activity not allowable for Alaska | |
| 2b | Other federal general business credits not allowable for Alaska | |
| 2c | Add lines 2a–2b | |
| 3 | Line 1 minus line 2c (Credits applicable to Alaska) | |
| 4 | Applicable general business credit from passive activity (Form 6395 line 17) | |
| 5 | Add lines 3 and 4 | |
| 6 | Apportionment factor | |
| 7 | Line 5 × line 6 | |
| 8 | Total apportioned general business credit (Multiply line 7 by 0.18) | |
| 9 | Alaska carryforward of general business credit | |
| 10 | Alaska carryback of general business credit | |
| PART II — Allowable Credit | ||
| 12a | Alaska regular tax (Form 6000/6100/6150 Schedule D line 2) | |
| 12b | Alaska incentive credits allowed against regular tax | |
| 12c | Line 12a minus line 12b (not less than zero) | |
| 13a | Net Alaska alternative minimum tax | |
| 13b | Alaska incentive credits against AMT | |
| 13c | Line 13a minus line 13b (not less than zero) | |
| 14 | Net Alaska income tax (add lines 12c and 13c) | |
| 15 | 25% of excess of line 12c over $4,500 | |
| PART IV — Tax Limitation | ||
| 29a | Net Alaska income tax (enter amount from line 14) | |
| 29b | Enter amount from line 15 | |
| 29c | Line 29a minus line 29b (not less than zero) | |
| 30 | Enter amount from line 17 | |
| 31 | Limitation: line 29c minus line 30 | |
| 32 | Smaller of line 28 or line 31 | |
| 33 | Credit allowed for the current year (Add lines 17 and 32; enter on Form 6000/6100/6150 Schedule A line 8) | |
Understanding Alaska’s Approach to Federal-Based Credits
Alaska is one of the few states that does not impose an individual income tax but maintains a detailed and sophisticated corporate income tax system. Federal-based business credits play an important role in this structure, especially for companies engaged in resource development, manufacturing, transportation, engineering and other capital-intensive sectors.
Form 6390 ensures consistency and prevents over-claiming of credits by aligning Alaska’s tax framework with federal credit limitations while also adjusting for Alaska-only considerations such as AMT treatment and apportionment. This prevents distortion where a corporation might generate federal credits unrelated to Alaska operations and then apply them disproportionately to reduce Alaska tax liability.
Businesses operating multiple facilities across states—common in oil & gas, shipping, logistics and construction—benefit greatly from correctly applying the apportionment factor. Errors in this area can result in significant underpayments or the loss of legitimate credit opportunities. Proper use of Form 6390 helps maintain conformity with the Alaska Department of Revenue’s requirements and ensures defensible tax reporting.
Last reviewed: 2025-11-12: If you believe this form requires an update, please contact us.
Additional Resources
- Federal Form 1120 Calculator
- Federal Form 3800 Calculator
- Alaska Form 6000 – Corporation Net Income Tax Return
- Alaska Form 6100 – S Corporation Return
- Alaska Form 6150 – Oil & Gas Corporation Tax Return
Corporations using federal general business credits should review Form 6390 annually, especially when tax liability, credit types or apportionment factors change. The calculator ensures a precise and compliant Alaska-specific computation of allowable credits and carryover amounts.
Quick Access Tools
Frequently Asked Questions
Do Anchorage or Fairbanks tax income?
No. Neither Anchorage nor Fairbanks taxes individual wages. Anchorage historically debated implementing a municipal income tax as an alternative to property taxes, but such measures have never passed. Fairbanks relies on property taxes and user fees. As a result, residents and workers in both cities benefit from Alaska’s statewide 0% income-tax policy with no additional local payroll deductions.
If I move to Alaska mid-year, do I immediately stop paying state income tax?
Yes. Once you become an Alaska resident, no state income tax applies to wages earned from that point forward. You must still file a part-year return for the state you moved from, reporting income earned before establishing Alaska residency. Alaska requires no part-year return, residency declaration or supplemental state forms. Your federal obligations remain unchanged, but Alaska offers instant relief from state withholding the moment your employer updates your work location or residency information.
If I open an LLC in Alaska, will I owe any state income tax?
For single-member LLCs treated as disregarded entities and traditional pass-through entities, Alaska imposes no state income tax at the individual or pass-through level. The income flows through to your federal return, and no Alaska filing is required. However, certain corporations—including C-corporations operating in Alaska—*are* subject to Alaska corporate income tax. LLCs electing C-corp treatment must follow those rules. For most small business owners, Alaska remains one of the most tax-advantaged jurisdictions in the United States.
How do pre-tax benefits like HSAs or FSAs affect take-home pay in Alaska?
HSAs, FSAs, dependent care FSAs and similar pre-tax benefits reduce federal taxable wages and often reduce FICA taxes. Alaska’s lack of a state tax means there is no second layer of savings or rules to track. As a result, tax planning involving pre-tax benefits is cleaner and easier for Alaska residents, since all tax effects occur at the federal level.
Where can I access a structured version of Alaska Form 6220?
A structured and calculator-ready version of the form is available at AK-6220 Underpayment Calculator, including line-by-line fields and automated penalty estimation.
Important Notes
All calculations are estimates for guidance only. Always review your return and consider professional advice when submitting official filings.