! amounts of Tier 1 Employee Additional Medicare

CAUTION Tax unless the amounts weren’t withheld from

employee compensation.

Example—You want your credit applied to Form CT-1. You filed your 2024 Form CT-1 on February 24, 2025, and payments were timely made. On May 5, 2025, you discover that you overreported tax on your 2024 Form CT-1. You file Form CT-1 X on June 3, 2025, and check the box on line 1 to indicate you want to use the adjustment process. The IRS treats your credit as a tax deposit made on January 1, 2025. When you file your 2025 Form CT-1, include the amount from Form CT-1 X, line 26, on the “Total railroad retirement tax deposits” line of your 2025 Form CT-1.

Overreported tax—Claim process. If you overreported tax on Form CT-1, you may choose to file a claim for refund or abatement on Form CT-1 X any time before the period of limitations on credit or refund for Form CT-1 expires. If you also need to correct any underreported tax amounts, you must file another Form CT-1 X reporting only corrections to the underreported tax amounts. See Is There a Deadline for Filing Form CT-1 X, later.