Exhibit 8.1

LIST OF SIGNIFICANT SUBSIDIARIES

The following is a list of ArcelorMittal’s significant operating subsidiaries as of December 31, 2020, each wholly- or majority-owned directly or indirectly through intermediate holding companies

Name of Subsidiary	Abbreviation	Country
NAFTA
ArcelorMittal Dofasco G.P.	ArcelorMittal Dofasco	Canada
ArcelorMittal México S.A. de C.V.	ArcelorMittal Mexico	Mexico
ArcelorMittal USA LLC1	ArcelorMittal USA	USA
ArcelorMittal Long Products Canada G.P.	ArcelorMittal Long Products Canada	Canada
Brazil and neighboring countries ("Brazil")
ArcelorMittal Brasil S.A.	ArcelorMittal Brasil	Brazil
Acindar Industria Argentina de Aceros S.A.	Acindar	Argentina
Europe
ArcelorMittal France S.A.S.	ArcelorMittal France	France
ArcelorMittal Belgium N.V.	ArcelorMittal Belgium	Belgium
ArcelorMittal España S.A.	ArcelorMittal España	Spain
ArcelorMittal Flat Carbon Europe S.A.	AMFCE	Luxembourg
ArcelorMittal Poland S.A.	ArcelorMittal Poland	Poland
ArcelorMittal Eisenhüttenstadt GmbH	ArcelorMittal Eisenhüttenstadt	Germany
ArcelorMittal Bremen GmbH	ArcelorMittal Bremen	Germany
ArcelorMittal Méditerranée S.A.S.	ArcelorMittal Méditerranée	France
ArcelorMittal Belval & Differdange S.A.	ArcelorMittal Belval & Differdange	Luxembourg
ArcelorMittal Hamburg GmbH	ArcelorMittal Hamburg	Germany
ArcelorMittal Duisburg GmbH	ArcelorMittal Duisburg	Germany
ArcelorMittal International Luxembourg S.A.	ArcelorMittal International Luxembourg	Luxembourg
ArcelorMittal Italia S.p.A.2	ArcelorMittal Italia	Italy
Africa and Commonwealth of Independent States ("ACIS")
ArcelorMittal South Africa Ltd.	ArcelorMittal South Africa	South Africa
JSC ArcelorMittal Temirtau	ArcelorMittal Temirtau	Kazakhstan
PJSC ArcelorMittal Kryvyi Rih	ArcelorMittal Kryvyi Rih	Ukraine
Mining
ArcelorMittal Mining Canada G.P. and ArcelorMittal Infrastructure Canada G.P.	ArcelorMittal Mines and Infrastructure Canada ("AMMC")	Canada
ArcelorMittal Liberia Ltd	ArcelorMittal Liberia	Liberia
JSC ArcelorMittal Temirtau	ArcelorMittal Temirtau	Kazakhstan
PJSC ArcelorMittal Kryvyi Rih	ArcelorMittal Kryvyi Rih	Ukraine

1. On December 9, 2020, the Company completed the sale of ArcelorMittal USA. See "—Key transactions and events in 2020" and note 2.3.1 to the consolidated financial statements.

2. On December 10, 2020, the Company signed a binding agreement with Invitalia, an Italian state-owned company, to form a public-private partnership between the parties. As a result, the carrying amount of the assets and liabilities of ArcelorMittal Italia was classified as held for sale at December 31, 2020 and will be accounted for under the equity method upon closing of the first investment (expected in the first quarter of 2021). See "Introduction—Key transactions and events in 2020" and note 2.3.2 for further information.