Cal. Code Regs. tit. 18 § 13951.5
In any case in which it is established that the value per share or bond on the basis of selling or bid and asked prices does not reflect the market value of a security, other relevant facts and elements of value will also be considered in determining its market value. A case of this kind would include one in which the sale of a listed stock on the date of the transferor's death was made at a price arrived at on the basis of erroneous, false, and misleading information concerning the affairs and financial condition of the issuing corporation.
The so-called "blockage rule" is not recognized in determining the value of securities for inheritance tax purposes.
NOTE: Reference: Section 13951, Revenue and Taxation Code.
Cal. Code Regs. Tit. 18, § 13951.5