26 CFR § 25.6001-1 - Records required to be kept.
(a) In general. Every person subject to taxation under Chapter 12 of the Internal Revenue Code of 1954 shall for the purpose of determining the total amount of his gifts, keep such permanent books of account or records as are necessary to establish the amount of his total gifts (limited as provided by section 2503(b)), together with the deductions allowable in determining the amount of his taxable gifts, and the other information required to be shown in a gift tax return. All documents and vouchers used in preparing the gift tax return (see § 25.6019-1) shall be retained by the donor so as to be available for inspection whenever required.
(b) Supplemental data. In order that the Internal Revenue Service may determine the correct tax the donor shall furnish such supplemental data as may be deemed necessary by the Internal Revenue Service. It is, therefore, the duty of the donor to furnish, upon request, copies of all documents relating to his gift or gifts, appraisal lists of any items included in the total amount of gifts, copies of balance sheets or other financial statements obtainable by him relating to the value of stock constituting the gift, and any other information obtainable by him that may be necessary in the determination of the tax. See section 2512 and the regulations issued thereunder. For every policy of life insurance listed on the return, the donor must procure a statement from the insurance company on Form 712 and file it with the internal revenue officer with whom the return is filed. If specifically requested by an internal revenue officer, the insurance company shall file this statement direct with the internal revenue officer.