California Code, Financial Code - FIN § 4930

(a) After a conversion becomes effective, the commissioner shall issue, upon application, a certificate under his or her official seal, stating that the converting depository corporation converted into the resulting depository corporation and specifying the time at which the conversion became effective.

(b) Any certificate issued pursuant to subdivision (a) shall be prima facie evidence of the fact of the conversion and of the regularity of the proceedings taken for the conversion and shall be conclusive evidence of such matters in favor of any innocent purchaser or encumbrancer for value.