FA-62543 / Tax bracket computation / Member archive

The 28% AMT rate is applied to the whole base once it crosses the break · case 03

Crossing the 232600 break raises the tax on the entire base by two points.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

solve(amti, regular_cents, status): stipulated AMT, whole dollars. Exemption: single 85700 (phase-out threshold 609350), mfj 133300 (threshold 1218700). The exemption is reduced by 25% of AMTI above the threshold, with the reduction rounded down to whole dollars, never below 0. Base = max(0, amti - exemption). Tentative minimum tax = 26% of base up to 232600 plus 28% of base above 232600 (in cents: dollars times percent). AMT = max(0, TMT - regular tax). Return [exemption, tmt_cents, amt_cents].

Why this case matters

Tax computations hinge on which slice, threshold, ordering and rounding rule applies at each step; a misplaced boundary silently misstates liabilities.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression rate-break 1	`[112975, 33236700, 3236700]`	`[112975, 32771500, 2771500]`	Failed

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