Cal. Code Regs. tit. 18, § 15802
There is no statutory period limiting the time within which the Controller may issue a deficiency determination where a false or fraudulent return is filed or where gifts are made for which no return is filed. In such a case, the Controller may issue a deficiency determination at any time.
If a gift tax return is timely filed, but the return fails to disclose all gifts made by the donor during the calendar quarter for which the return is filed, the Controller may issue a deficiency determination for the unreported gifts at any time, regardless of the reason for failure to include the same in the return filed.
Note: Reference: Section 15802, Revenue and Taxation Code.