Instructions for Form 6251 – 2017 Tax Year Checklist
Introduction
This guide supports accurate Alternative Minimum Tax work for the 2017 income tax return using the correct line structure and exemption rules in effect before the central Tax Cuts and
Jobs Act changes. Although the Tax Cuts and Jobs Act was enacted in late 2017, most AMT revisions apply after 2017, so the 2017 system continues to follow pre-TCJA mechanics under the Internal Revenue Code.
The Alternative Minimum Tax compares the tentative minimum tax to the regular income tax after refiguring selected tax benefits under separate rules. When the tentative amount exceeds the regular tax, the difference is reported as Additional Taxes on Form 1040, the US Individual
Income Tax Return.
Before the Checklist: What to Gather and What Not to Mix
Use the correct 2017 Form 6251 with the matching Federal Form 1040 or 1040NR US
Nonresident Alien Income Tax Return, because line references differ in later tax years. Confirm the income tax return package matches the 2017 instructions, not later versions influenced by the Tax Cuts and Jobs Act.
Gather Schedule A, Schedule D, Schedule E, and any Schedule K-1 documents that affect AMT adjustments, including incentive stock options and passive activity differences. Keep state
items, such as Form 540, Long Form 540NR, or California Schedule CA (540 or 540NR),
separate, because California adjustments follow different rules than federal law.
Step-by-Step Checklist (10 Steps)
Step 1: Confirm the Correct Form and Tax Year
Verify the return uses the 2017 Form 6251 and aligns with the 2017 Federal Form 1040 or
1040NR filing. Mixing later forms, such as Federal Form 1040A or 1040EZ Income Tax Return, can distort AMT adjustments.
Step 2: Identify the Proper Starting Income Line
Use taxable income from the correct line of the 2017 Form 1040 as the AMT starting point.
Confirm the filing status and ensure no later-year exemption amounts are substituted.
Step 3: Refigure Itemized Deductions
Review Schedule A deductions, especially property taxes and certain miscellaneous items that may be limited under Alternative Minimum Tax rules. Enter only the difference required as AMT adjustments, not the entire deduction amount.
Step 4: Add Preference Items Such as Private Activity Bond Interest
Include specified private activity bond interest in Alternative Minimum Taxable Income as required by the 2017 instructions. Do not offset this income unless permitted under IRC Section
58 or related Internal Revenue Code guidance.
Step 5: Address Qualified Small Business Stock
If a Section 1202 exclusion was claimed, compute the AMT preference separately and enter it on the correct Form 6251 line. Ensure the gain reported matches Schedule D and brokerage statements in the income tax return.
Step 6: Compute Incentive Stock Options Adjustments
For exercised incentive stock options not sold in 2017, calculate the spread between fair market value and exercise price as an AMT adjustment. Maintain separate AMT basis records for prior years to avoid errors in later capital gain reporting.
Step 7: Recompute Gains or Losses on Property
If the AMT basis differs due to depreciation or prior adjustments, recompute the gain using
Schedule D and related forms. Enter only the difference between the regular tax and AMT results on Form 6251.
Step 8: Refigure Passive Activity Amounts
Recalculate passive activity income or loss under AMT rules when Schedule E items or tax shelter farm activity apply. Maintain separate AMT carryforwards to preserve correct future-year calculations.
Step 9: Apply the 2017 AMT Exemption and Phaseout
Apply the correct 2017 exemption amount based on filing status and reduce it when AMTI exceeds phaseout thresholds. Base this calculation on Alternative Minimum Taxable Income, not Adjusted Gross Income.
- Full IRS transcript retrieval (Wage & Income + Account)
- Professional tax form review
- Preparation & filing support
- Tax relief options if you owe the IRS
Step 10: Compute Tentative Minimum Tax and Compare
Apply the 26% and 28% AMT rates, and complete the capital gains worksheet when required.
Compare the tentative minimum tax to the regular income tax after allowable credits, such as the Foreign Tax Credit, and apply additional taxes if needed.
Common Mistakes to Avoid
Confusing AMT adjustments with California adjustments or applying California Revenue and
Taxation Code provisions to a federal computation leads to errors. Mixing Form 540 2EZ, Form
FTB 3514, or other state credits, such as the California Earned Income Tax Credit, into Form
6251 results in incorrect totals.
Another frequent error involves ignoring AMT basis tracking for incentive stock options, which affects future capital gain reporting. Failing to separate regular tax credit limitations from AMT credit limitations can also misstate tax liability.
Frequently Asked Questions
Does the Tax Cuts and Jobs Act change 2017 AMT calculations?
For 2017 returns, the Alternative Minimum Tax largely follows pre-TCJA rules under federal law.
Later exemption increases apply to subsequent tax years.
Are incentive stock options always subject to AMT?
Incentive stock options often create AMT adjustments when exercised but not sold in the same year. The adjustment reflects the spread between fair market value and exercise price.
Do Social Security or employment taxes affect Form 6251?
Social Security and Medicare, along with employment taxes reported on Schedule SE, are separate from Alternative Minimum Tax computations. They do not directly change AMT taxable income.
Should state forms be attached to Form 6251?
State forms such as Form 540 or Form 540NR, or references to the California Revenue and
Taxation Code, are not part of the federal AMT computation. Keep federal and state calculations separate.
Closing
Accurate completion of Form 6251 for the 2017 tax year requires careful comparison between regular income tax and Alternative Minimum Tax rules under the Internal Revenue Code.
Maintaining organized records for prior years, incentive stock options, passive activity, and AMT adjustments reduces future reporting errors.
A methodical review of each line, supported by proper documentation from Schedule A,
Schedule D, and Schedule E, ensures compliance with 2017 tax laws. Careful tracking also
supports future planning for NOL carryback issues, credit limitations, and potential AMT credits in later years.
If you’re missing tax documents or want to ensure the numbers you enter match IRS records, we can help.
