UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): October 23, 2025 (October 20, 2025)

CSX CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (904) 359-3200

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act ☐

See Item 8.01

On October 23, 2025, CSX Corporation (the “Company”) completed a public offering of $300,000,000 aggregate principal amount of the Company’s 5.050% Notes due 2035 (the “Notes”). The Notes constitute a further issuance of, and will form a single series with, the Company’s outstanding 5.050% Notes due 2035 issued on March 10, 2025 in an initial aggregate principal amount of $600,000,000. The Notes were issued pursuant to an indenture, dated as of August 1, 1990, between the Company and The Bank of New York Mellon Trust Company, N.A. (formerly known as The Bank of New York Trust Company, N.A.), successor to JPMorgan Chase Bank, N.A. (formerly known as The Chase Manhattan Bank), as trustee, as supplemented by a First Supplemental Indenture dated as of June 15, 1991, a Second Supplemental Indenture dated as of May 6, 1997, a Third Supplemental Indenture dated as of April 22, 1998, a Fourth Supplemental Indenture dated as of October 30, 2001, a Fifth Supplemental Indenture dated as of October 27, 2003, a Sixth Supplemental Indenture dated as of September 23, 2004, a Seventh Supplemental Indenture dated as of April 25, 2007, an Eighth Supplemental Indenture dated as of March 24, 2010, a Ninth Supplemental Indenture, dated as of February 12, 2019, a Tenth Supplemental Indenture, dated as of December 10, 2020 and an Eleventh Supplemental Indenture, dated as of July 28, 2022 (collectively, the “Indenture”) and an Action of Authorized Pricing Officers of the Company dated as of October 20, 2025. The offering of the Notes was made pursuant to the Company’s shelf registration statement on Form S-3ASR (Registration No. 333-285319) which became effective February 27, 2025. On October 22, 2025, the Company filed with the Securities and Exchange Commission, pursuant to Rule 424(b)(2) under the Securities Act of 1933, its Prospectus, dated February 27, 2025, and Prospectus Supplement, dated October 20, 2025, pertaining to the offering and sale of the Notes.

The foregoing summary is qualified by reference to the Action of Authorized Pricing Officers of the Company and the form of global note for the offering, which are filed as exhibits to this Current Report on Form 8-K and are incorporated by reference herein and in the above-referenced shelf registration statement.

(d) The following exhibits are being filed herewith:

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.