The discriminatory amounts (i.e., the excess reimbursements) are included in the HCIs’ gross income and should be reported on Form W-2, Box 1. If the plan year has already closed and W-2s have already been issued, then the employer must issue amended Form W-2s to the HCIs who received excess reimbursements, and those HCIs would be responsible for filing an amended individual federal income tax return to correct their gross income reported to the Internal Revenue Service (IRS) (assuming the individuals already filed such a return).