As used in this chapter:
The rulings and regulations of the internal revenue service and decisions of the federal courts defining the principles applicable in determining fair market value for purposes of the federal estate tax imposed by Subchapter A, Chapter 11 of the Internal Revenue Code shall be applied in determining fair market value for purposes of the estate taxes imposed by this chapter, to the extent that these rulings, regulations, and decisions are not inconsistent with the express provisions of this chapter, but the actual determination of the fair market value by the internal revenue service of any asset included in the gross estate is not controlling for purposes of the estate taxes imposed by this chapter, unless the person filing the estate tax return and the tax commissioner have agreed in writing to be bound by the federal determination, as provided in section 5731.26 of the Revised Code.
If a valuation of securities is undertaken by reference to market transactions and if the block of securities to be valued is so large in relation to actual sales on existing markets that it could not be liquidated in a reasonable time without depressing the market, the price at which the block could be sold, as such, outside the usual market, as through an underwriter, shall be considered in determining the value of such block of securities.
No deduction under this chapter of any item shall be allowed if allowance is, in effect, given by use of the alternate valuation date. In the determination of any tax liability of any estate in which an election is filed under this division, all provisions in this chapter that refer to value at the time of the decedent's death shall be construed for all purposes to mean the value of such property used in determining the value of the gross estate. For the purposes of the charitable deduction under section 5731.17 of the Revised Code, any bequest, legacy, devise, or transfer enumerated in it shall be valued as of the date of the decedent's death with adjustment for any difference in value, not due to mere lapse of time or the occurrence or nonoccurrence of a contingency, of the property as of the date six months after the decedent's death, or in case of its earlier disposition, on such date of disposition.
An election under this division shall be exercised on the estate tax return by the person required to file the return. When made, an election under this division is irrevocable. An election cannot be exercised under this division if a return is filed more than one year after the time prescribed, including any extensions of time granted, pursuant to law for filing the return.
R.C. § 5731.01