SoftBank Block Sale of 13M T-Mobile Shares Ends Schedule 13D Status

Rhea-AI Filing Summary

The Reporting Persons—SoftBank Group Corp. and affiliated entities—filed Amendment No. 18 to their Schedule 13D for T-Mobile US common stock. On August 6, 2025 Project 4 LLC, Project 6 LLC and Project 9 LLC sold an aggregate of 13,000,000 shares in an unregistered block sale under Rule 144 for net proceeds of approximately $3.02 billion, representing about 1.16% of outstanding common stock as of July 18, 2025. Individual sale breakdown: Project 4 sold 3,566,400 shares, Project 6 sold 182,043, and Project 9 sold 9,251,557. As a result, the Reporting Persons’ collective beneficial ownership fell below 5% and this Amendment is the final Schedule 13D filing; the cover pages show SoftBank beneficially owns 50,861,065 shares (4.52%). The filing also states the Reporting Persons will continue to monitor and evaluate their investment.

Positive

• Net proceeds of approximately $3.02 billion realized from the block sale on August 6, 2025.
• Final Schedule 13D amendment filed because the Reporting Persons’ collective ownership fell below the 5% threshold.
• Sale size documented: 13,000,000 shares sold, representing approximately 1.16% of outstanding shares as of July 18, 2025.

Negative

• Collective beneficial ownership declined below 5%, with SoftBank reported at 50,861,065 shares (4.52%) after the sale.
• Reduction in disclosed stake from prior filings may change the Reporting Persons’ regulatory reporting status and public disclosure scope.

Insights

Financial Analyst

TL;DR: SoftBank executed a 13M-share block sale for ~$3.02B, lowering collective ownership below 5% and ending Schedule 13D reporting.

The transaction is clearly documented in the amendment: 13,000,000 shares sold on August 6, 2025 for net proceeds of about $3.02 billion, equal to ~1.16% of the outstanding common stock as of July 18, 2025. The filing reports post-sale beneficial ownership for SoftBank of 50,861,065 shares (4.52%), and states this is the final amendment because the Reporting Persons no longer exceed the 5% reporting threshold. These facts are material to disclosure and shareholder registries.

Corporate Governance Expert

TL;DR: Crossing below the 5% threshold ends reporting duties; the amendment documents a definitive block sale and post-sale ownership figures.

The Schedule 13D amendment records the mechanics and scale of the block sale, the specific share counts sold by each Project LLC, and the legal conclusion that the Reporting Persons will cease to be Section 13(d) Reporting Persons. The filing reiterates that certain shares were held by Project entities and subject to a Proxy Agreement as previously disclosed. The document is procedural and focused on disclosure compliance.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 18)

T-Mobile US, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

872590104

(CUSIP Number)

Kenneth A. Siegel, Esq.
Shin-Marunouchi Building, 29th Floor, 5-1, Marunouchi 1-Chome
Chiyoda-ku, Tokyo, M0, 100-6529
81-3-3214-6522

John Horsfield-Bradbury, Esq.
1 New Fetter Lane,
London, X0, EC4A 1AN
44 20 7959 8491

Robert G. DeLaMater, Esq.
125 Broad Street,
New York, NY, 10004
1-212-558-4788

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

08/06/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 872590104

1

Name of reporting person

SoftBank Group Capital Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED KINGDOM

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.00 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 872590104

1

Name of reporting person

Delaware Project 4 L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.00 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP No. 872590104

1

Name of reporting person

Delaware Project 6 L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 32,861,065.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

32,861,065.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.92 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

(1) Based on the number of shares of Common Stock outstanding on July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. (The terms used above are defined in the Explanatory Note of this Schedule 13D).

SCHEDULE 13D

CUSIP No. 872590104

1

Name of reporting person

Delaware Project 9 L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 18,000,000.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

18,000,000.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.60 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

(1) Based on the number of shares of Common Stock outstanding on July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. (The terms used above are defined in the Explanatory Note of this Schedule 13D).

SCHEDULE 13D

CUSIP No. 872590104

1

Name of reporting person

SoftBank Group Corp.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

JAPAN

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 50,861,065.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

50,861,065.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.52 %

14

Type of Reporting Person (See Instructions)

HC, CO

Comment for Type of Reporting Person:

(1) As of the date hereof, the shares of Common Stock are held by Project 6 LLC, a wholly owned subsidiary of SoftBank, and Project 9 LLC, a wholly owned subsidiary of SoftBank; the shares of Common Stock held by Project 6 LLC and Project 9 LLC are subject to the Proxy Agreement. (2) Based on the number of shares of Common Stock outstanding on July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. (The terms used above are defined in the Explanatory Note of this Schedule 13D).

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock
(b)	Name of Issuer: T-Mobile US, Inc.
(c)	Address of Issuer's Principal Executive Offices: 12920 SE 38TH STREET, BELLEVUE, WASHINGTON , 98006.
Item 1 Comment: EXPLANATORY NOTE This Amendment No. 18 (this "Schedule 13D Amendment") to the Schedule 13D filed with the U.S. Securities and Exchange Commission (the "Commission") on April 2, 2020, as amended and supplemented by Amendment No. 1 to the Schedule 13D filed with the Commission on June 15, 2020, Amendment No. 2 to the Schedule 13D filed with the Commission on June 25, 2020, Amendment No. 3 to the Schedule 13D filed with the Commission on June 26, 2020, Amendment No. 4 to the Schedule 13D filed with the Commission on July 30, 2020, Amendment No. 5 to the Schedule 13D filed with the Commission on October 6, 2020, Amendment No. 6 to the Schedule 13D filed with the Commission on September 7, 2021, Amendment No. 7 to the Schedule 13D filed with the Commission on September 9, 2021, Amendment No. 8 to the Schedule 13D filed with the Commission on September 16, 2021, Amendment No. 9 to the Schedule 13D filed with the Commission on September 28, 2021, Amendment No. 10 to the Schedule 13D filed with the Commission on February 4, 2022, Amendment No. 11 to the Schedule 13D filed with the Commission on March 29, 2022, Amendment No. 12 to the Schedule 13D filed with the Commission on April 13, 2022, Amendment No. 13 to the Schedule 13D filed with the Commission on June 6, 2023, Amendment No. 14 to the Schedule 13D filed with the Commission on December 26, 2023, Amendment No. 15 to the Schedule 13D filed with the Commission on June 11, 2024, Amendment No. 16 to the Schedule 13D filed with the Commission on July 2, 2024 and Amendment No. 17 to the Schedule 13D filed with the Commission on June 20, 2025 (as amended and supplemented, this "Schedule 13D"), is being filed on behalf of SoftBank Group Corp., a Japanese kabushiki kaisha ("SoftBank"), its wholly owned subsidiary SoftBank Group Capital Limited, a private limited company incorporated in England and Wales ("SBGC"), SoftBank's wholly owned subsidiary Delaware Project 6 L.L.C., a Delaware limited liability company ("Project 6 LLC"), SoftBank's wholly owned subsidiary, Delaware Project 4 L.L.C., a Delaware limited liability company ("Project 4 LLC"), and SoftBank's wholly owned subsidiary, Delaware Project 9, L.L.C., a Delaware limited liability company ("Project 9 LLC," and together with SoftBank, SBGC, Project 6 LLC and Project 4 LLC, the "Reporting Persons"), with respect to the common stock of T-Mobile US, Inc., a Delaware corporation ("T-Mobile" or the "Issuer"), par value $0.00001 per share (the "Common Stock"). Other than as set forth below, all Items in the Schedule 13D are materially unchanged. Capitalized terms used in this Schedule 13D Amendment which are not defined herein have the meanings given to them in this Schedule 13D.
Item 4.	Purpose of Transaction
	Item 4 of the Schedule 13D is hereby amended to include the following: On August 6, 2025, Project 4 LLC, Project 6 LLC and Project 9 LLC collectively sold an aggregate of 13,000,000 shares of Common Stock in an unregistered block sale transaction with an unaffiliated broker dealer pursuant to Rule 144 under the Securities Act of 1933, as amended (the "Block Sale") for net proceeds of approximately $3.02 billion, representing approximately 1.16% of the shares of Common Stock outstanding as of July 18, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q, filed with the Commission on July 23, 2025. Project 4 LLC sold 3,566,400 shares of Common Stock, Project 6 LLC sold 182,043 shares of Common Stock and Project 9 LLC sold 9,251,557 shares of Common Stock. The Block Sale was undertaken as part of the Reporting Persons' normal course evaluation of their investment. Although the Reporting Persons do not have any specific plan or proposal to effect further sales of shares of Common Stock at the time of this filing, the Reporting Persons intend to monitor and evaluate their investment on an ongoing basis. As a result of the Block Sale, the Reporting Persons no longer collectively beneficially own greater than five percent of the number of shares of Common Stock outstanding and therefore this Amendment No. 18 represents the final amendment to the Schedule 13D and the Reporting Persons shall cease to be Reporting Purposes immediately after the filing of this Amendment No. 18.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5 of the Schedule 13D is hereby amended to include the following: The information contained in the cover pages of this Schedule 13D is incorporated herein by reference.
(b)	The information contained in the cover pages of this Schedule 13D is incorporated herein by reference.
(c)	The information contained in Item 4 of this Schedule 13D is herein incorporated by reference. Other than as set forth in this Schedule 13D Amendment, none of the Reporting Persons nor, to the best of each Reporting Person's knowledge, any person on Appendix A-1, Appendix A-2, Appendix A-3, Appendix A-4 or Appendix A-5 (each as previously filed with the Schedule 13D), has engaged in any transaction in any shares of Common Stock since the filing of Amendment No. 17 to the Schedule 13D on June 20, 2025.
(e)	The Reporting Persons collectively ceased to have beneficial ownership of greater than five percent of the number of shares of Common Stock outstanding on August 6, 2025.

SIGNATURE

After reasonable 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.

SoftBank Group Capital Limited

Signature:	/s/ Stephen Lam
Name/Title:	Stephen Lam, Director
Date:	08/08/2025

Delaware Project 4 L.L.C.

Signature:	/s/ Hugh Manahan
Name/Title:	Hugh Manahan, Manager
Date:	08/08/2025

Delaware Project 6 L.L.C.

Signature:	/s/ Hugh Manahan
Name/Title:	Hugh Manahan, Manager
Date:	08/08/2025

Delaware Project 9 L.L.C.

Signature:	/s/ Hugh Manahan
Name/Title:	Hugh Manahan, Manager
Date:	08/08/2025

SoftBank Group Corp.

Signature:	/s/ Yuko Yamamoto
Name/Title:	Yuko Yamamoto, Head of Corporate Legal Department
Date:	08/08/2025

FAQ

How many TMUS shares did SoftBank and its affiliates sell?

The filing states an aggregate of 13,000,000 shares were sold in the block sale on August 6, 2025.

What were the proceeds from the block sale of TMUS shares?

The Reporting Persons received net proceeds of approximately $3.02 billion from the block sale.

What percentage of T-Mobile (TMUS) outstanding stock did the sale represent?

The sale represented about 1.16% of common stock outstanding as of July 18, 2025 (per the issuer's reported outstanding shares).

What is SoftBank’s ownership of TMUS after the sale?

The cover pages report SoftBank beneficially owns 50,861,065 shares, equal to 4.52% of the class after the transaction.

Will SoftBank continue to sell more TMUS shares?

The filing states the Reporting Persons do not have any specific plan or proposal to effect further sales at the time of filing and intend to monitor and evaluate their investment on an ongoing basis.

Why is this Amendment No. 18 described as the final amendment?

The Amendment states that as a result of the Block Sale the Reporting Persons no longer collectively beneficially own greater than 5% and therefore this Amendment is the final Schedule 13D amendment.