and the principal purpose for which such acquisition was made is evasion or avoidance of tax under this part by securing the benefit of a deduction, credit, or other allowance which such person or corporation would not otherwise enjoy, then such deduction, credit, or other allowance shall not be allowed. For purposes of this subdivision, control means the ownership of stock possessing at least 50 percent of the total combined voting power of all classes of stock entitled to vote or at least 50 percent of the total value of shares of all classes of stock of the corporation.
Ca. Rev. and Tax. Code § 24431