The commissioner shall be the custodian of all collateral in the form of stock certificates, bonds, debentures, notes and other evidences of indebtedness deposited or pledged with the commissioner under any existing law, and it shall be the commissioner's official duty safely to keep, surrender and account for the collateral deposited as provided by law, and for the safekeeping of that collateral both the commissioner and the sureties on the commissioner's official bond are liable.