FA-58864 / Payroll withholding rules / Member archive

Social security wage-base withholding: cent rounding of tax · case 04

Withholding is a cent short whenever 6.2% of taxable wages has a fractional cent of one half or more.

Member previewVariant 4 · 3 implementations · 10 checks per implementation

Case contract

Input {ytd, lines:[[kind, cents]], base, exempt}. Social security wages are reg+ot+bonus+tips minus sec125 (401k deferrals do not reduce them), floored at 0. Exempt employees owe nothing ([0,0]). Taxable = min(wages, max(0, base-ytd)); tax = 6.2% rounded half-up to the cent. Return [taxable, tax].

Why this case matters

Employee social security withholding must stop exactly at the annual wage base and use the FICA wage definition, not the income-tax one.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression 0	`[96979, 6012]`	`[96979, 6013]`	Failed

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