Cal. Rev. & Tax. Code § 18794

There is in the State Treasury the California Breast Cancer Research Voluntary Tax Contribution Fund to receive contributions made pursuant to Section 18793. The Franchise Tax Board shall notify the Controller of both the amount of money paid by taxpayers in excess of their tax liability and the amount of refund money which taxpayers have designated pursuant to Section 18793 to be transferred to the California Breast Cancer Research Voluntary Tax Contribution Fund. The Controller shall transfer from the Personal Income Tax Fund to the California Breast Cancer Research Voluntary Tax Contribution Fund an amount not in excess of the sum of the amounts designated by individuals pursuant to Section 18793 for payment into that fund.