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 Alaska residents need to keep tax documents for state audit purposes?
No. Alaska cannot audit your income because it does not impose income tax. However, the IRS may audit your federal return, and you should maintain documentation accordingly. For businesses, corporations, and certain credits (e.g., oil & gas or education credits), Alaska may conduct audits, but these do not apply to individual wage earners.
Is Form 6230 only for overpayments made early in the year?
No. Overpayment can occur in any installment period, including late-year projections. For example, if a corporation makes a large catch-up payment in Q3 based on assumed revenue that fails to materialize in Q4, that installment may be refundable. Form 6230 covers excess across the entire estimated-payment framework. The key requirement is that the corporation can compute and justify a lower estimated annual tax liability than originally projected.
How accurate are the 2026 Alaska tax tables?
They are based entirely on IRS updates for federal withholding, Social Security and Medicare. Because Alaska has no state income tax, the tables require no state adjustments, no bracket updates and no annual state-level legislative review. This makes Alaska one of the simplest states in which to compute net pay accurately. All tools are refreshed annually with IRS inflation adjustments, ensuring alignment with federal standards.
How does a corporation determine whether it has “nexus” in Alaska?
Nexus is established when a corporation has sufficient business activity within Alaska to create a tax obligation. This generally includes maintaining a physical presence, conducting sales or services with sustained in-state operations, having employees in Alaska, owning or leasing property, or deriving Alaska-source revenue. Alaska also follows economic-presence principles for certain industries, notably oil, gas and pipeline companies, meaning nexus can arise even with limited physical footprint. If a corporation has any recurring business activity in Alaska, it must typically file Form 6000 unless specifically exempt.
Are commuter or transit taxes withheld in Alaska?
No. Alaska does not impose commuter, transit, or regional mobility taxes that appear in some other states (such as Oregon's statewide transit tax or certain city-based earnings taxes). Regardless of where you live—Anchorage, Fairbanks, Juneau, the Kenai Peninsula, rural villages, or North Slope communities—there is no payroll-based commuter tax. Any transportation fees that do exist, such as ferry system fares or airport surcharges, are paid by users directly and never deducted from wages. This makes Alaska particularly attractive for remote workers or employees who commute substantial distances, because commuting never triggers payroll-related assessments tied to location.
Important Notes
All calculations are estimates for guidance only. Always review your return and consider professional advice when submitting official filings.