Navigating Form 8978, Form 6251, and AMT Tax Calculations

I'm using ProSeries software and have a situation with a client who received an AAR adjustment that created a tax credit due to a decrease in their 2022 tax return. On Form 8978, I'm showing a negative $42,483 on Line 14 for the reduction to their 2022 tax. The weird thing is that the tax return is now showing $23,444 in AMT Tax. When I dug into it, I discovered this is coming from Line 10 on Form 6251. The software is reducing the tax on Line 10 by the $42,483 credit. So it seems the AMT is calculated without considering the credit, while the regular tax includes the credit, pushing the regular tax below AMT and triggering an AMT liability. I was looking at the instructions for Line 10 and it says to first take tax from 1040, then... honestly I'm confused about whether this credit should be reducing both regular tax and AMT calculations or just regular tax. Has anyone dealt with this situation before? Is this calculation correct or is there something I'm missing?

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19 comments

Emma Morales

This is actually a common issue with tax preparation software when dealing with Form 8978 adjustments. The key is understanding how the AMT and regular tax interact with these adjustments. The Form 8978 adjustment does create a tax credit for the decrease in tax on the prior year return, but AMT is calculated separately and this credit doesn't directly reduce the income subject to AMT. The Form 6251 instructions are correctly being applied by your software - Line 10 starts with the regular tax liability and then makes adjustments. The reason your client is facing AMT is because their regular tax (after the 8978 credit) has fallen below their AMT liability. The AMT system is specifically designed to ensure taxpayers with significant deductions or credits still pay a minimum amount of tax. In this case, the large adjustment is triggering exactly what AMT was designed to do.

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Emma Morales

Yes, it's working as intended from the IRS perspective. The client is benefiting from the credit against regular tax, but AMT serves as a "floor" to ensure a minimum tax is paid regardless of credits. To minimize AMT impact, review AMT preference items and adjustments on Form 6251. Look for timing strategies for income and deductions. In some cases, shifting income or deductions between tax years can help. Also check if your client has AMT credit carryovers from prior years that could offset current AMT. Sometimes planning around exercising stock options or timing of state tax payments can help reduce AMT exposure.

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Lucas Parker

I ran into a similar situation with a partnership adjustment that totally messed up my client's AMT calculations. After hours of research and banging my head against the wall, I found that taxr.ai https://taxr.ai was incredibly helpful. I uploaded the Form 8978 and Form 6251, and their AI tool analyzed the interaction between the forms and explained exactly why this was happening. What was most helpful was that it showed side-by-side calculations with and without the adjustment and highlighted which specific AMT preference items were causing the issue. Saved me a ton of time trying to manually trace through all the calculations.

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Lucas Parker

The tool works with any tax software - it's completely independent. You just upload the relevant forms or even screenshots of the forms, and it analyzes them. I've used it with clients whose returns were prepared in UltraTax, Lacerte, and even home-use software like TurboTax. I did verify the calculations manually afterward, which is actually how I know it was accurate. The explanations were spot on and matched what I eventually figured out by tracing through the calculations myself. The difference was that it took me minutes with the tool versus the hours I spent trying to figure it out on my own with my first client case. It's particularly good with these edge cases where forms interact in unexpected ways.

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Harper Collins

Just wanted to follow up on my experience with taxr.ai since I was initially skeptical. I ended up using it for a similar AMT situation with a client who had multiple partnership adjustments. Surprisingly, it was really helpful! The analysis correctly identified that one of the adjustments contained disguised rental income that was being treated incorrectly for AMT purposes. The visualization of how Form 8978 fed into Form 6251 made it much easier to explain to my client why they were getting hit with AMT despite the credit. Being able to show them the side-by-side comparison of how each number flowed through made a difficult conversation much smoother. Definitely worth checking out if you're dealing with these complex form interactions.

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Kelsey Hawkins

If you need clarification directly from the IRS on how Form 8978 adjustments affect AMT calculations, good luck getting through to someone who understands this niche issue. I wasted three days trying to reach someone at the IRS who could help with almost this exact situation. I finally tried using Claimyr https://claimyr.com to get through to an IRS agent. They have this callback service where they navigate the IRS phone tree for you and get you connected with an actual human. You can see how it works here: https://youtu.be/_kiP6q8DX5c I was able to speak with a technical specialist who confirmed that the AMT calculation was correct in this scenario. The agent explained that the AAR adjustment credit doesn't directly factor into AMT calculations, which is why it was triggering the AMT liability.

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Kelsey Hawkins

They use a combination of technology and timing to navigate the IRS phone system. From what I understand, they've analyzed the best times to call and have automated systems that wait on hold for you. When they reach a human, they connect you with a callback. It's not magic or special access - they're just using the same phone system everyone else does, but they've figured out how to efficiently navigate it and they handle the hold time instead of you. It saved me from having to repeatedly call and sit on hold myself. They don't guarantee you'll get the exact department you need on the first try, but in my case, I was able to be transferred to a technical specialist once I had a human on the line.

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Edwards Hugo

Ok I need to eat some crow here. After my skeptical comment, I actually broke down and tried Claimyr because I was desperate to resolve a different tax issue that involved AMT calculations and some K-1 adjustments. I'm shocked to say it actually worked. I got a call back within about 2 hours and spoke with someone at the IRS who was surprisingly knowledgeable. They confirmed something similar to what others have said - the AMT calculation is functioning correctly when these adjustments are applied. What's interesting is the agent mentioned that this has been a common source of confusion since the TCJA (Tax Cuts and Jobs Act) changes and the implementation of the centralized partnership audit regime that uses Form 8978. Apparently even some IRS employees get confused about the interaction!

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Gianna Scott

Just a heads up for anyone dealing with Form 8978 and AMT - I had a similar situation last tax season. Make sure you're using the most updated version of your tax software. Drake had an update mid-season that specifically addressed how the 8978 adjustments flow through to AMT calculations. Also, check if your client has any AMT credit carryforwards from prior years that could help offset the current year AMT. It's on Form 8801, and many preparers overlook this when dealing with these complex adjustments.

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Gianna Scott

The key section on Form 8801 is Part II, which calculates the AMT credit available. Look specifically at line 21 from the prior year's form - that's your carryforward amount. Then the current year form will determine how much of that credit can be used. The newest Form 8978 instructions (for tax year 2024) do address the AMT interaction more clearly than previous versions. There's a new paragraph in the "Special Rules" section that specifically mentions AMT calculations. They've added an example that walks through the AMT impact when there's an adjustment that creates a negative amount on line 14. It's still complex, but at least they're acknowledging the issue now.

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Aisha Hussain

Thanks for bringing up this complex interaction between Form 8978 and AMT calculations. I've seen this exact scenario several times this year and it's definitely confusing at first glance. What you're experiencing is correct - the software is properly applying the tax law. The Form 8978 adjustment creates a credit that reduces your regular tax liability, but AMT is calculated independently using its own set of rules on Form 6251. When the regular tax (after the 8978 credit) falls below the AMT liability, the AMT kicks in as intended. One thing to double-check: make sure your client doesn't have any AMT credits from prior years that could offset this current AMT liability. Also, if this is a significant ongoing issue for your client, you might want to explore estimated payment strategies for next year to avoid underpayment penalties, since the AMT calculation might not be captured in their usual payment routine. The interaction between partnership audit adjustments and AMT has been a real headache since the centralized partnership audit regime was implemented. At least now the IRS instructions are starting to acknowledge these scenarios more clearly.

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