N.Y. Comp. Codes R. & Regs. tit. 20, § 18-3.1
(b) The adjusted eligible net income of a IBF is computed by subtracting from eligible gross income the following:
(c) An IBF is required to:
(2) maintain books and records that accurately reflect gross income, gains, losses, deductions, assets, liabilities and other activities of the IBF for the taxable year, and make available to the Tax Commission upon its request any information necessary to substantiate the deduction determined in this Subpart. Such information may include, but shall not be limited to:
Tax Law, § 1453(f)