DEXCOM INC

To the stockholders and the Board of Directors of DexCom, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheet of DexCom, Inc. and subsidiaries (the “Company”) as of December 31, 2025, the related consolidated statements of operations, comprehensive income, stockholders’ equity, and cash flows, for the year ended December 31, 2025, and the related notes and the schedule listed in the Index at Item 15(a) (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025, and the results of its operations and its cash flows for the year ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control —Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 12, 2026, expressed an unqualified opinion on the Company’s internal control over financial reporting.

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audit included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audit also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audit provides a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Pharmacy Rebates in the United States — Refer to Note 1. Revenue Recognition – Variable Consideration to the financial statements

Critical Audit Matter Description

As disclosed in Note 1 to the financial statements, when revenue is recognized, the Company includes an estimate of variable consideration in the calculation of the transaction price. Variable consideration includes, but is not limited to, rebates, chargebacks, product returns provision, and prompt payment discounts. The Company classifies these items as a liability unless the criteria for right of offset are met; in such cases, the Company may classify these items as a reduction of accounts receivable.

The Company is subject to rebates on pricing programs with managed care organizations, such as pharmacy benefit managers, government, and third-party payors. The estimate of pharmacy rebates in the United States (collectively, “U.S. pharmacy rebates”) involves the consideration of contractual arrangements, estimates of products sold subject to rebate, known events or trends, and channel inventory data. Given the subjectivity and complexity of evaluating management’s assumptions used in the estimation of U.S. pharmacy rebates, auditing U.S. pharmacy rebates requires a high degree of auditor judgment and an increased extent of effort.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the U.S. pharmacy rebates included the following, among others:

•We tested the effectiveness of certain controls related to management’s assessment of assumptions related to estimating the U.S. pharmacy rebates reserve and the associated variable consideration.

•We evaluated the appropriateness and consistency of the Company’s methods and assumptions used to calculate the U.S. pharmacy rebates reserve and the associated variable consideration by:

◦Testing the underlying data, including historical and current year gross sales to distributor customers, rebate payments, and inventory sold reported from distributors.

◦Evaluating the Company’s ability to estimate the U.S. pharmacy rebates accrual accurately by comparing actual amounts incurred for the U.S. pharmacy rebates accruals to historical estimates.

◦Evaluating known events or trends affecting the U.S. pharmacy rebates.

/s/Deloitte & Touche LLP

San Diego, CA

February 12, 2026

We have served as the Company’s auditor since 2025.

To the Stockholders and the Board of Directors of DexCom, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheet of DexCom, Inc. (the Company) as of December 31, 2024, the related consolidated statements of operations, comprehensive income, stockholders’ equity and cash flows for each of the two years in the period ended December 31, 2024, and the related notes and financial statement schedule listed in the Index at Item 15(a) (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles.

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

/s/Ernst & Young LLP

We served as the Company’s auditor from 2000 to 2025.

San Diego, California

February 14, 2025