Individual-tax coverage for business and itemized deductions, AMT, and estimated-tax planning.
This chapter moves from AGI to taxable income and related payment obligations. The main TCP task is to understand where deductions belong, which limitations apply, and how alternative systems like AMT or estimated-tax rules affect the final answer.
Deduction questions should be solved after the income base is stable. A deduction can be allowed, limited, reclassified, displaced by AMT, or irrelevant for estimated-tax purposes depending on where it sits in the computation.
| Topic | Main question | Exam risk |
|---|---|---|
| Business versus personal deductions and QBI | Is the expense tied to a trade or business, personal activity, or qualified business income computation? | Treating a personal item as business-related, or applying QBI before the taxable-income limitation is understood. |
| Itemized deductions | Does the taxpayer benefit from itemizing after statutory floors, caps, and substantiation rules? | Memorizing a deduction category without checking whether the facts satisfy timing, percentage, or documentation limits. |
| AMT | Does the item change the regular-tax answer, the AMT answer, or both? | Assuming a regular-tax deduction produces the same benefit under the parallel AMT system. |
| Estimated tax | Has the taxpayer paid enough throughout the year under a safe harbor or current-year standard? | Solving annual liability correctly but missing payment-timing penalties. |
| Step | What to do | Why it matters on TCP |
|---|---|---|
| 1. Confirm the income base | Start from gross income and AGI before applying deductions or parallel tax systems. | Deduction limits often depend on AGI or taxable income thresholds. |
| 2. Classify each deduction | Separate business, above-the-line, itemized, QBI, personal, and nondeductible items. | Classification determines where the item enters the computation. |
| 3. Apply statutory limits | Check floors, caps, percentage limits, substantiation, timing, and taxable-income limits. | A deductible item may be partially allowed or unavailable in the current year. |
| 4. Test AMT and payment effects | Determine whether AMT adjustments or estimated-tax rules change the final exposure. | Liability and payment timing can diverge from the regular-tax answer. |
| 5. Compare planning alternatives | Evaluate bunching, charitable timing, QBI constraints, safe harbors, and penalty avoidance. | TCP emphasizes the best supportable result, not only the mechanical deduction total. |
| Checkpoint | Exam use | What to avoid |
|---|---|---|
| Computation layer | Place the item above the line, below the line, in itemized deductions, in QBI, or outside the computation. | Classifying an expense by intuition instead of where the Code allows it. |
| Limitation base | Identify AGI, taxable income, business income, percentage floors, caps, or substantiation requirements. | Applying a deduction limit to the wrong base. |
| Timing and documentation | Check paid or incurred timing, charitable records, business purpose, and required substantiation. | Assuming an otherwise deductible item is allowed without proof. |
| AMT interaction | Determine whether the item is allowed, adjusted, or disallowed under the parallel AMT system. | Carrying the regular-tax answer into AMT without adjustment. |
| Payment exposure | Test withholding, estimated payments, safe harbors, and underpayment penalties after annual liability is known. | Solving total tax while ignoring when the tax had to be paid. |