Personalis, Inc.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, 2025 December 31, 2024 2025 2024 2025 2024 ModernaTX, Inc. 19% 33% 25% 28% 11% * Regeneron Pharmaceuticals 19% * * * 19% * Pfizer Inc. 11% * * * 12% 25% Natera, Inc. * 20% 10% 31% * 13% Merck & Co., Inc. * * * * 18% 31% VA MVP * 17% 15% 11% * * * Less than 10% of revenue or accounts receivable.Significant Accounting PoliciesAs of September 30, 2025, the Company’s significant accounting policies are consistent with those discussed in Note 2 - “Summary of Significant Accounting Policies” in its consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended June 30, Six Months Ended June 30, June 30, 2026 December 31, 2025 2026 2025 2026 2025 Merck & Co., Inc. (1) 37% 11% 30% * 49% 12% VA MVP 13% 19% 15% 20% * * ModernaTX, Inc. 12% 29% 14% 28% * * Natera, Inc. * 13% * 13% * * US Department of Veterans Affairs * * * * * 24% AstraZeneca UK Limited * * * * * 10% * Less than 10% of revenue or accounts receivable.(1) Consists of related party revenue and related party accounts receivable, respectively.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended March 31, March 31, 2026 December 31, 2025 2026 2025 Merck & Co., Inc. (1) 19% * 33% 12% VA MVP 16% 20% * * Moderna, Inc. 16% 27% 14% * Natera, Inc. * 12% * * Genentech, Inc. * * 22% * US Department of Veterans Affairs * * * 24% AstraZeneca UK Ltd * * * 10% * Less than 10% of revenue or accounts receivable (1) Consists of related party revenue and related party receivable, respectively.

Moderna accounted for 22% and 28% and the VA MVP accounted for 17% and 9% of our revenue for the years ended December 31, 2025 and 2024, respectively.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, 2025 December 31, 2024 2025 2024 2025 2024 ModernaTX, Inc. 19% 33% 25% 28% 11% * Regeneron Pharmaceuticals 19% * * * 19% * Pfizer Inc. 11% * * * 12% 25% Natera, Inc. * 20% 10% 31% * 13% Merck & Co., Inc. * * * * 18% 31% VA MVP * 17% 15% 11% * * * Less than 10% of revenue or accounts receivable.Significant Accounting PoliciesAs of September 30, 2025, the Company’s significant accounting policies are consistent with those discussed in Note 2 - “Summary of Significant Accounting Policies” in its consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, 2025 December 31, 2024 2025 2024 2025 2024 ModernaTX, Inc. 19% 33% 25% 28% 11% * Regeneron Pharmaceuticals 19% * * * 19% * Pfizer Inc. 11% * * * 12% 25% Natera, Inc. * 20% 10% 31% * 13% Merck & Co., Inc. * * * * 18% 31% VA MVP * 17% 15% 11% * * * Less than 10% of revenue or accounts receivable.Significant Accounting PoliciesAs of September 30, 2025, the Company’s significant accounting policies are consistent with those discussed in Note 2 - “Summary of Significant Accounting Policies” in its consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended June 30, Six Months Ended June 30, June 30, 2026 December 31, 2025 2026 2025 2026 2025 Merck & Co., Inc. (1) 37% 11% 30% * 49% 12% VA MVP 13% 19% 15% 20% * * ModernaTX, Inc. 12% 29% 14% 28% * * Natera, Inc. * 13% * 13% * * US Department of Veterans Affairs * * * * * 24% AstraZeneca UK Limited * * * * * 10% * Less than 10% of revenue or accounts receivable.(1) Consists of related party revenue and related party accounts receivable, respectively.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Year Ended December 31, December 31, 2025 2024 2025 2024 Moderna, Inc. 22% 28% * * VA MVP 17% * * * US Department of Veterans Affairs * * 24% * Merck & Co., Inc. * * 12% 31% AstraZeneca UK Ltd * * 10% * Pfizer Inc. * * * 25% Natera, Inc. * 30% * 13% * Less than 10% of revenue or accounts receivableRevenue RecognitionThe Company applies the revenue recognition guidance in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers, (“ASC Topic 606”).The Company derives revenue from the sale of genomic testing services.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended March 31, March 31, 2026 December 31, 2025 2026 2025 Merck & Co., Inc. (1) 19% * 33% 12% VA MVP 16% 20% * * Moderna, Inc. 16% 27% 14% * Natera, Inc. * 12% * * Genentech, Inc. * * 22% * US Department of Veterans Affairs * * * 24% AstraZeneca UK Ltd * * * 10% * Less than 10% of revenue or accounts receivable (1) Consists of related party revenue and related party receivable, respectively.

For example, revenue under our agreement with Natera accounted for 30% of our total revenue for the year ended December 31, 2024 and only 8% of our total revenue for the year ended December 31, 2025.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended June 30, Six Months Ended June 30, June 30, 2026 December 31, 2025 2026 2025 2026 2025 Merck & Co., Inc. (1) 37% 11% 30% * 49% 12% VA MVP 13% 19% 15% 20% * * ModernaTX, Inc. 12% 29% 14% 28% * * Natera, Inc. * 13% * 13% * * US Department of Veterans Affairs * * * * * 24% AstraZeneca UK Limited * * * * * 10% * Less than 10% of revenue or accounts receivable.(1) Consists of related party revenue and related party accounts receivable, respectively.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended March 31, March 31, 2026 December 31, 2025 2026 2025 Merck & Co., Inc. (1) 19% * 33% 12% VA MVP 16% 20% * * Moderna, Inc. 16% 27% 14% * Natera, Inc. * 12% * * Genentech, Inc. * * 22% * US Department of Veterans Affairs * * * 24% AstraZeneca UK Ltd * * * 10% * Less than 10% of revenue or accounts receivable (1) Consists of related party revenue and related party receivable, respectively.

Natera accounted for 8% and 30% of our revenue for the years ended December 31, 2025 and 2024, respectively.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Three Months Ended September 30, Nine Months Ended September 30, September 30, 2025 December 31, 2024 2025 2024 2025 2024 ModernaTX, Inc. 19% 33% 25% 28% 11% * Regeneron Pharmaceuticals 19% * * * 19% * Pfizer Inc. 11% * * * 12% 25% Natera, Inc. * 20% 10% 31% * 13% Merck & Co., Inc. * * * * 18% 31% VA MVP * 17% 15% 11% * * * Less than 10% of revenue or accounts receivable.Significant Accounting PoliciesAs of September 30, 2025, the Company’s significant accounting policies are consistent with those discussed in Note 2 - “Summary of Significant Accounting Policies” in its consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024.

Multiple customers have provided more than 10% of total revenue in the periods presented, or accounted for more than 10% of accounts receivable at each respective balance sheet date, as follows: Revenue Accounts Receivable Year Ended December 31, December 31, 2025 2024 2025 2024 Moderna, Inc. 22% 28% * * VA MVP 17% * * * US Department of Veterans Affairs * * 24% * Merck & Co., Inc. * * 12% 31% AstraZeneca UK Ltd * * 10% * Pfizer Inc. * * * 25% Natera, Inc. * 30% * 13% * Less than 10% of revenue or accounts receivableRevenue RecognitionThe Company applies the revenue recognition guidance in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers, (“ASC Topic 606”).The Company derives revenue from the sale of genomic testing services.

Our suppliers, including Illumina, could cease supplying these materials and equipment at any time, could increase the price of these materials or equipment (including the promotional pricing offered to us by Illumina for our 2022 VA MVP Agreement and certain other projects) or fail to provide us with sufficient quantities of materials or equipment that meet our specifications.