T Mobile US : 2023 Reasonable Assurance Statement

INDEPENDENT REASONABLE ASSURANCE STATEMENT

To: The Stakeholders of T-Mobile USA, Inc.

Introduction and objectives of work

Apex Companies, LLC (Apex) has been engaged by T-Mobile USA, Inc. (T-Mobile) to provide reasonable (Scope1 and Scope 2) and limited (Scope 3) assurance of its greenhouse gas (GHG) emissions and energy use data for calendar year 2023. This assurance statement applies to the data and information included within the scope of work described below.

This information and its presentation are the sole responsibility of the management of T- Mobile. Our sole responsibility was to provide independent assurance on the accuracy of the reported data and information, and on the underlying systems and processes used to collect, analyze and review the information.

Scope of work

The scope of our work was limited to assurance over greenhouse (GHG) emissions and energy use data for the period January 1, 2023 to December 31, 2023 (the "Subject Matter").

• Energy use (direct and indirect)
• Renewable electricity purchased in 2023
• Scope 1 GHG emissions
• Scope 2 (location-andmarket-based) GHG emissions
• Scope 3 GHG emissions

1. Category 1 - Purchased goods and services o Category 2 - Capital goods
   o Category 3 - Fuel- and energy-related activities (market-based)o Category 4 - Upstream transportation and distribution
   o Category 5 - Waste generated in operations o Category 6 - Business travel
   o Category 7 - Employee commuting
   o Category 9 - Downstream transportation and distribution o Category 11 - Use of sold products
   o Category 12 - End-of-life treatment of sold products

Data and information supporting the energy use, Scope 1 and Scope 2 GHG emissions were primarily historical in nature.

Data and information supporting the Scope 3 GHG emissions were in some cases estimated rather than historical in nature.

Reporting Boundaries

The following are the boundaries used by T-Mobile for reporting sustainability data:

• Operational Control
• United States and Puerto Rico

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Reporting Criteria

The reporting criteria for greenhouse gas emissions was the World Resources Institute (WRI)/World Business Council for Sustainable Development (WBCSD) Greenhouse Gas Protocol Corporate Accounting and Reporting Standard. Energy use data was collected and reported based on T-Mobile's standard procedures and guidelines for sustainability reporting.

Limitations, Exclusions, and Qualifications

Excluded from the scope of our work is any assurance of information relating to:

• Activities outside the defined verification period of Calendar Year 2023
• Activities outside of the United States and Puerto Rico
• Activities outside T-Mobile's operational control
• Legacy Sprint international sites that do not have data in the data collection system

This assurance engagement (both reasonable and limited) relies on a risk based selected sample of sustainability data and the associated limitations that this entails. The reliability of the reported data is dependent on the accuracy of metering and other production measurement arrangements employed at site level, not addressed as part of this assurance. This independent statement should not be relied upon to detect all errors, omissions or misstatements that may exist.

Responsibilities

This preparation and presentation of the data and information are the sole responsibility of the management of T-Mobile.

Apex was not involved in the drafting of the Report or of the Reporting Criteria. Our responsibilities were to:

• obtain reasonable (Scope 1 and Scope 2) and limited (Scope 3) assurance about whether the Subject Matter has been prepared in accordance with the Reporting Criteria;
• form an independent conclusion based on the assurance procedures performed and evidence obtained; and
• report our conclusions to the Stakeholders of T-Mobile.

Assessment Standards

• We performed our work in accordance with Apex's standard procedures and guidelines for external Assurance and International Standard on Assurance Engagements (ISAE) 3000 Revised, Assurance Engagements Other than Audits or Reviews of Historical Financial Information (effective for assurance reports dated on or after Dec. 15, 2015), issued by the International Auditing and Assurance Standards Board. Greenhouse Gas Emissions were verified in accordance with and ISO Standard 14064-3 (Second edition 2019-4) Greenhouse Gases - Part 3: Specification with guidance for the verification and validation of greenhouse gas statements. A materiality threshold of ±5-percent was set for the assurance process.

Summary of Work Performed

As part of our independent verification, our work included:

1. Assessing the appropriateness of the Reporting Criteria for the data and information;
2. Conducting interviews with relevant personnel of T-Mobile regarding data collection and reporting systems;
3. Reviewing the data collection and consolidation processes used to compile Subject Matter, including assessing assumptions made, and the data scope and reporting boundaries;

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1. Reviewing documentary evidence provided by T-Mobile;
2. Agreeing a selection of the data and information to the corresponding source documentation;
3. Reviewing T-Mobile and Legacy Sprint systems for quantitative data aggregation and analysis.
4. Assessing the disclosure and presentation of the data and information to ensure consistency with assured information.

Conclusion

Energy Statement

On the basis of our methodology and the activities described above, it is our opinion that:

• The Energy & Renewable Energy data and information reported by T-Mobile is presented in accordance with the Reporting Criteria and is, in all material respects, fairly stated.
• T-Mobilehas established appropriate systems for the collection, aggregation and analysis of quantitative data within the scope of this assurance.

Scope 1 and 2 GHG Emissions Statement

On the basis of our methodology and the activities described above, it is our opinion that the data and information:

• is materially correct and is a fair representation of the GHG emissions data and information; and
• is prepared in accordance with the WRI/WBCSD GHG Protocol Corporate Accounting and Reporting Standard (Scope 1 and 2).

Scope 3 GHG Emissions Statement

On the basis of our methodology and the activities described above, it is our opinion there is no evidence that the data and information:

• is not a fair representation of the GHG emissions data and information; and
• has not been prepared in accordance with the WRI/WBCSD Greenhouse Gas Protocol Corporate Value Chain Accounting and Reporting Standard (Scope 3).

A summary of data within the scope of assurance for 2023 is attached.

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Statement of Independence, Integrity and Competence

Apex is an independent professional services company that specializes in Health, Safety, Social and Environmental management services including assurance with over 30 years history in providing these services.

Apex has implemented a Code of Ethics across the business to maintain high ethical standards among staff in their day-to-day business activities.

No member of the assurance team has a business relationship with T-Mobile, its Directors or Managers beyond that required of this assignment. We have conducted this verification independently, and there has been no conflict of interest.

The assurance team has extensive experience in conducting assurance over environmental, social, ethical and health and safety information, systems and processes, has over 20 years combined experience in this field and an excellent understanding of Apex's standard methodology for the assurance of sustainability related assertions.

Thomas U. Jones, Lead Verifier	Trevor Donaghu, Technical Reviewer
ESG Program Manager	ESG Director
Apex Companies, LLC	Apex Companies, LLC
Tampa, Florida	Pleasant Hill, California
March 6, 2024

This verification opinion declaration, including the opinion expressed herein, is provided to T-Mobile and is solely for the benefit of T- Mobile in accordance with the terms of our agreement. We consent to the release of this declaration to the public or other organizations, but without accepting or assuming any responsibility or liability on our part to any other party who may have access to this declaration.

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Summary of 2023 Data Subject to Assurance

Metric Type	Units(1)
Direct Energy
Natural Gas	MWh
Propane	MWh
Diesel Fuel	MWh
Fleet Fuel	MWh
Total Direct Energy	MWh
Indirect Energy
Purchased Electricity	MWh
Purchased Renewable Electricity	MWh
Scope 1 GHG emissions	MT CO2e
Scope 2 GHG emissions
Location-Based	MT CO2e
Market-Based	MT CO2e
Scope 3 GHG Emissions
Category 1 - Purchased goods and services	MT CO2e
Category 2 - Capital goods	MT CO2e
Category 3 - Fuel- and energy-related activities	MT CO2e
Category 4 - Upstream transportation and	MT CO2e
distribution
Category 5 - Waste generated in operations	MT CO2e
Category 6 - Business travel	MT CO2e
Category 7 - Employee commuting	MT CO2e
Category 9 -Downstream transportation and	MT CO2e
distribution
Category 11 - Use of sold products
Direct Use-Phase	MT CO2e
Indirect Use-Phase	MT CO2e
Category 12 - End-of-life treatment of sold	MT CO2e
products
Total Scope 3 GHG Emissions	MT CO2e
(1) Unit abbreviations:
MT CO2e = metric tons of carbon dioxide equivalents
MWh = megawatt hours

2023

47,008

3,746

46,593

94,664

192,011

7,482,584

7,482,584

66,851

2,818,195

0

2,316,949

1,402,496

204,340

455,612

28,536

37,778

113,382

356,650

1,028,866

212,351

31,082

6,188,041

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