26 CFR § 1.1244(e)-1 - Records to be kept.
(a) By the corporation -
(1) Mandatory records. A plan to issue pre-November 1978 stock must appear upon the records of the corporation. Any designation of post-November 1978 stock under § 1.1244(c)-2(b)(2) also must appear upon the records of the corporation.
(iv) Financial statements of the corporation, such as its income tax returns, that identify the source of the gross receipt of the corporation for the period consisting of the five most recent taxable years of the corporation, or, if the corporation has not been in existence for 5 taxable years, for the period of the corporation's existence;
(v) Information relating to any tax-free stock dividend made with respect to section 1244 stock and any reorganization in which stock is transferred by the corporation in exchange for section 1244 stock; and
(vi) With respect to pre-November 1978 stock;
(B) The amount of money and the basis in the hands of the corporation of other property received after June 30, 1958, and before the adoption of the plan, for its stock, as a contribution to capital, and as paid-in surplus; and
(b) By the taxpayer. A person who claims an ordinary loss with respect to stock under section 1244 must have records sufficient to establish that the taxpayer is entitled to the loss and satisfies the requirements of section 1244. See also section 6001, requiring records to be maintained.