Personalis Inc

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Stockholders and Board of Directors

Personalis, Inc.

Fremont, California

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated balance sheets of Personalis, Inc. and subsidiaries (the Company) as of December 31, 2024 and 2023, the related consolidated statements of operations, comprehensive loss, stockholders’ equity, and cash flows for each of the years then ended, and the related notes (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 2023, and the results of its operations and its cash flows for each of the years then, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s consolidated financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (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 consolidated financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated 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 consolidated 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 consolidated financial statements. We believe that our audits provide 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 consolidated 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 consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing separate opinions on the critical audit matter or on the accounts or disclosures to which it relates.

Revenue Transactions

As described in Notes 2 and 3 to the consolidated financial statements, the Company derives revenue from the sale of genomic testing services. The genomic testing services are the only distinct services that meet the definition of a performance obligation and are accounted for as one performance obligation. Revenue is recognized at a point in time when test results are transferred to the customer. The Company’s consolidated revenue was $84.6 million for the year ended December 31, 2024.

We identified the auditing of the occurrence of revenue transactions as a critical audit matter. Auditing the occurrence of revenue was especially challenging due to the significant audit effort in performing procedures related to the occurrence of revenue transactions, given the significance of revenue, the large volume of transactions, and the evaluation of the sufficiency of audit evidence.

The primary procedures we performed to address this critical audit matter included:

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Evaluating the occurrence of revenue transactions, on a sample basis, by obtaining and inspecting invoices, customer purchase orders, delivery data from various sources including confirmation of transactions with customers, and cash receipts from customers, where applicable.

/s/BDO USA, P.C.

We have served as the Company's auditor since 2023.

San Jose, California

February 27, 2025