(a) Bonds issued pursuant to this part are made and declared to be (1) legal investments for savings banks and trustees unless otherwise provided in the instrument creating the trust, (2) securities in which all public officers and bodies, all insurance companies and associations and persons carrying on an insurance business, all banks, bankers, trust companies, savings banks and savings associations, including savings and loan associations, investment companies and persons carrying on a banking or investment business, all administrators, guardians, executors, trustees and other fiduciaries and all persons whatsoever who are or may be authorized to invest in bonds of the state, may properly and legally invest funds including capital in their control or belonging to them, and (3) securities which may be deposited with and shall be received by all public officers and bodies for any purpose for which the deposit of bonds of the state is or may be authorized.
(b) All special obligation bonds, issued pursuant to this part, their transfer and the income therefrom including any profit on the sale or transfer thereof shall at all times be exempt from all taxation by the state or under its authority.