17 CFR § 210.2-06 - Retention of audit and review records.
(a) For a period of seven years after an accountant concludes an audit or review of an issuer's financial statements to which section 10A(a) of the Securities Exchange Act of 1934 (15 U.S.C. 78j-1(a)) applies, or of the financial statements of any investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8), the accountant shall retain records relevant to the audit or review, including workpapers and other documents that form the basis of the audit or review, and memoranda, correspondence, communications, other documents, and records (including electronic records), which:
(1) Are created, sent or received in connection with the audit or review, and
(2) Contain conclusions, opinions, analyses, or financial data related to the audit or review.
(b) For the purposes of paragraph (a) of this section, workpapers means documentation of auditing or review procedures applied, evidence obtained, and conclusions reached by the accountant in the audit or review engagement, as required by standards established or adopted by the Commission or by the Public Company Accounting Oversight Board.
(c) Memoranda, correspondence, communications, other documents, and records (including electronic records) described in paragraph (a) of this section shall be retained whether they support the auditor's final conclusions regarding the audit or review, or contain information or data, relating to a significant matter, that is inconsistent with the auditor's final conclusions regarding that matter or the audit or review. Significance of a matter shall be determined based on an objective analysis of the facts and circumstances. Such documents and records include, but are not limited to, those documenting a consultation on or resolution of differences in professional judgment.