Cal. Rev. & Tax. Code § 17953

For purposes of computing “taxable income of a nonresident or part-year resident” under paragraph (1) of subdivision (i) of Section 17041, income of estates and trusts distributed or distributable to nonresident beneficiaries is income from sources within this state only if distributed or distributable out of income of the estate or trust derived from sources within this state. For the purposes of this section, the nonresident beneficiary shall be deemed to be the owner of intangible personal property from which the income of the estate or trust is derived.