For how many years must the W-4 form be retained?

The correct answer is based on the retention requirement for tax-related documents. Specifically, the W-4 form, which is used by employees to report their withholding allowances, must be kept for a period of four years. This timeframe is calculated from April 15 following the tax year for which the forms were used.

When considering tax documents, the IRS generally requires that employers retain these records to validate withholding amounts in case of audits or inquiries about employee tax obligations. The four-year period is aligned with the IRS's statute of limitations for tax assessments, which allows the IRS to audit a tax return for up to three years after the return is filed, and in some cases, longer for substantial underreporting.

In this context, retaining W-4 forms for four years ensures that the employer can accurately demonstrate compliance with tax withholding requirements, making it essential for good record-keeping practices.