Quantum-Si Inc

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Stockholders of Quantum-Si Incorporated

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Quantum-Si Incorporated and its subsidiaries (the“Company”) as of December 31, 2025 and 2024, and the related consolidated statements of operations and comprehensive loss, of changes in stockholders’ equity (deficit) and of cash flows for the years 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 2024, and the results of its operations and its cash flows for the years 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 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 of these consolidated financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits 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 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.

Lease Termination - Winchester

As described in Note 17 to the consolidated financial statements, in December 2021, the Company signed a 10-year lease with Winchester Office LLC (“Winchester”) as landlord. The lease commenced on January 8, 2022 with an original lease expiration date of July 31, 2032. On September 13, 2022, the Company filed a lawsuit against Winchester, alleging that Winchester had (i) refused to reimburse the Company for costs related to improvements already incurred and submitted, (ii) delayed the Company’s completion of improvements, in order to avoid reimbursing the costs of those improvements, and (iii) improperly rejected the Company’s proposed improvement plans. On September 23, 2025, the Company and Winchester entered into the mutual release agreement in connection with the lease. For the year ended December 31, 2025, the Company recorded $13.6 million of total lease termination expense, net, in consideration for Winchester’s agreement to terminate the lease as of the early termination date and settle all disputes between the parties.

The principal considerations for our determination that performing procedures relating to the lease termination - Winchester is a critical audit matter are a high degree of auditor effort in performing procedures and evaluating audit evidence related to the Company’s accounting for the lease termination.

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) obtaining and evaluating the lease and mutual release agreements; (ii) evaluating management’s assessment of the accounting treatment relating to the derecognition and settlement under the lease and mutual release agreements; (iii) confirming with internal and external counsel the extent to which the settlement is reasonably estimable; and (iv) evaluating the sufficiency of the Company’s disclosures in the consolidated financial statements.

/s/PricewaterhouseCoopers LLP

San Diego, California

March 3, 2026

We have served as the Company’s auditor since 2024.