UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

Tender Offer Statements under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

(Amendment No. 9)

MILLICOM INTERNATIONAL CELLULAR S.A.

(Name of Subject Company (Issuer))

ATLAS LUXCO S.À R.L.

(Offeror)

a wholly-owned subsidiary of

ATLAS INVESTISSEMENT

(Affiliate of Offeror)

a majority-owned subsidiary of

NJJ HOLDING

(Affiliate of Offeror)

wholly-owned by

XAVIER NIEL

(Affiliate of Offeror)

MAXIME LOMBARDINI

(Affiliate of Offeror)

(Name of Filing Persons (identify status as offeror, issuer or other person))

Common Shares, par value $1.50 per share

(Title of Class of Securities)

L6388F110

(CUSIP Number of Class of Securities)

Anthony Maarek

Directeur Général

Atlas Investissement 16 rue de la Ville l’Evêque 75008 Paris, France

Telephone: +33.1.42.66.99.19

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications on Behalf of Filing Persons)

Copies to:

Denis Klimentchenko

Skadden, Arps, Slate, Meagher & Flom (UK) LLP

22 Bishopsgate

London, EC2N 4BQ

+44(0)20 7519 7289

Check the appropriate boxes below to designate any transactions to which the statement relates:

Check the following box if the filing is a final amendment reporting the results of the tender offer: ¨

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of this transaction, passed upon the merits or fairness of this transaction, or passed upon the adequacy or accuracy of the disclosure herein. Any representation to the contrary is a criminal offense.

INTRODUCTION

This Amendment No. 9 (this “Amendment”) amends and supplements the Tender Offer Statement and Rule 13e-3 Transaction Statement filed under cover of Schedule TO filed with the US Securities and Exchange Commission (the “SEC”) on July 1, 2024 (as amended and supplemented by Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4, Amendment No. 5, Amendment No. 6, Amendment No. 7, Amendment No. 8, this Amendment and as further amended or supplemented from time to time, this “Tender Offer Statement and Rule 13e-3 Transaction Statement”) by Atlas Luxco S.à r.l., a Luxembourg limited liability company (société à responsibilité limitée) (“Purchaser”), Atlas Investissement, a French société par actions simplifiée and the parent company of Purchaser (“Parent”), NJJ Holding S.A.S., a simplified joint-stock company domiciled in Paris, France (société par actions simplifiée) and the majority owner of Parent (“NJJ”), Xavier Niel, the owner of NJJ (together with Purchaser, Parent and NJJ, the “Purchaser Group”), and Maxime Lombardini (together with the Purchaser Group, the “Filing Parties”), the Non-Executive Director, President and Chief Operating Officer of Millicom, as well as Vice-Chairman of the Board of Directors of Iliad Group, an affiliate of Purchaser and Parent.

This Tender Offer Statement and Rule 13e-3 Transaction Statement relates to the offer by Purchaser to purchase, through separate but concurrent offers in the United States (the “US Offer”) and Sweden (the “Swedish Offer”), all of the issued and outstanding common shares, par value $1.50 per share (each, a “Common Share,” and collectively, the “Common Shares”), including Swedish Depositary Receipts representing Common Shares (each of which represents one Common Share) (each, an “SDR,” and collectively, the “SDRs,” and together with Common Shares, the “Shares”), of Millicom International Cellular S.A., a public limited liability company (société anonyme) organized and established under the laws of the Grand Duchy of Luxembourg (“Millicom” or the “Company”), for USD 25.75 per Common Share and USD 25.75 per SDR (each such amount, the “Offer Price”), upon the terms and subject to the conditions set forth in the Offer to Purchase attached to this Tender Offer Statement and Rule 13e-3 Transaction Statement as Exhibit (a)(1)(A) (together with any amendments or supplements thereto, the “Offer to Purchase”) and in the accompanying Letter of Transmittal attached to this Tender Offer Statement and Rule 13e-3 Transaction Statement as Exhibit (a)(1)(B) (together with any amendments or supplements thereto, the “Letter of Transmittal” and together with the Offer to Purchase, the Letter of Transmittal and other materials related to the Swedish Offer and the US Offer, as each may be amended or supplemented from time to time, the “Offers”). Unless otherwise indicated, references to sections in this Tender Offer Statement and Rule 13e-3 Transaction Statement are references to sections of the Offer to Purchase.

Except as otherwise set forth in this Amendment, the information set forth in the Tender Offer Statement and Rule 13e-3 Transaction Statement remains unchanged and is incorporated herein by reference to the extent relevant to the items in this Amendment. Capitalized terms used but not defined herein have the meanings ascribed to them in the Offer to Purchase.

Items 1 through 9, Item 11 and Item 13.

The information contained in the Offer to Purchase and Items 1 through 9, Item 11 and Item 13 of the Tender Offer Statement and Rule 13e-3 Transaction Statement are hereby amended, restated and supplemented, as applicable, as follows:

“ The aggregate purchase price payable by Purchaser upon the consummation of the Offers will be approximately $496,186,457.75 and will be sourced by drawing down from the Long-Term Financing on the terms and provisions of the Senior Facilities Agreement, as amended, a copy of which is filed as an exhibit hereto and is incorporated herein by reference in its entirety.”

Item 12. Exhibits.

Item 12 of the Tender Offer Statement and Rule 13e-3 Transaction Statement is hereby supplemented as follows:

SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: August 28, 2024

EXHIBIT INDEX