ArcelorMittal

Foreign Filer Report • Dec 22, 2025

6-K 1 form6-kdec222025.htm 6-K Document created using Wdesk Copyright 2025 Workiva Document

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

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Dated December 22, 2025

Commission File Number: 001-35788

ARCELORMITTAL

(Translation of registrant’s name into English)

24-26, Boulevard d’Avranches

L-1160 Luxembourg

Grand Duchy of Luxembourg

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

On December 22, 2025, ArcelorMittal published the press release attached hereto as Exhibit 99.1 and hereby incorporated by reference into this report on Form 6-K.

Exhibit Index

Exhibit No. Description

Exhibit 99.1 Press release dated December 22, 2025, ArcelorMittal expands its portfolio of renewable energy projects

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, thereunto duly authorized.

ARCELORMITTAL

Date 22 December 2025

By: /s/ Henk Scheffer

Name: Henk Scheffer

Title: Company Secretary & Group Compliance & Data Protection Officer