COMPASS Pathways plc

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders of Compass Pathways plc

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheet of Compass Pathways plc and its subsidiaries (the "Company") as of December 31, 2025, and the related consolidated statements of operations and comprehensive loss, of shareholders' (deficit) equity and of cash flows for the year then ended, including 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 as of December 31, 2025, and the results of its operations and its cash flows for the year then ended 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 audit. 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 audit of these consolidated financial statements 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 audit 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 audit 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 audit 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 audit provides a reasonable basis for our opinion.

Critical Audit Matters

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 (i) relates to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters 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 a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

As described in Note 2 to the consolidated financial statements, the Company carries out extensive research and development (“R&D”) activities and benefits from the UK R&D tax credit regime. Under the UK R&D tax credit regime, the Company is able to claim a cash rebate based on a portion of such qualifying R&D expenditure. The Company assesses its research and development activities and expenditures to determine whether the nature of the activities and expenditures will qualify for credit under the UK R&D tax credit regime and whether the claims will ultimately be realized based on the allowable reimbursable expense criteria established by the U.K. government, which are subject to interpretation. For the portion of the expense that the Company expects to qualify under the programs and plans to submit a claim for, the Company records a benefit within other (expense) income, net which is included in the loss before income tax. For the year ended December 31, 2025, the Company’s benefit from UK R&D tax credit was $3.7 million.

The principal consideration for our determination that performing procedures relating to the benefit from research and development tax credit is a critical audit matter is a high degree of auditor effort in performing procedures related to the Company’s benefit from the UK R&D tax credit.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included, among others (i) evaluating management’s determination that the nature of the activities performed by the Company qualify for the UK R&D tax credit regime; (ii) for a sample of R&D expenditures, testing accuracy and existence by obtaining and inspecting source documents, such as the underlying contracts or agreements, purchase orders, invoices, payroll records, and information received from certain third party service providers, where applicable, and testing the eligibility and classification of expense type based on the relevant tax laws; (iii) testing management’s calculation of qualifying expenses based on the rates in the relevant tax laws; and (iv) testing management’s calculation of the UK R&D tax credit in accordance with relevant tax laws.

/s/PricewaterhouseCoopers LLP

Boston, Massachusetts

March 24, 2026

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

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders of Compass Pathways plc

Opinion on the Financial Statements

We have audited the consolidated balance sheet of Compass Pathways plc and its subsidiaries (the “Company”) as of December 31, 2024, and the related consolidated statements of operations and comprehensive loss, of shareholders’ (deficit) equity, and of cash flows for the year then ended, including 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 as of December 31, 2024, and the results of its operations and its cash flows for the year then ended 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 audit. 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 audit of these consolidated financial statements 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.

Our audit 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 audit 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 audit provides a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Reading, United Kingdom

February 27, 2025

We served as the Company's auditor from 2018 to 2025.