Sec. 4. (a) A savings bank may purchase, invest in, and dispose of any of the following:
(1) Notes or bonds secured by mortgage or trust deed insured by the federal housing administrator.
(2) Debentures issued by the federal housing administrator.
(3) Bonds or other securities issued by national mortgage associations.
(b) An Indiana law:
(1) prescribing the nature, amount, or form of security;
(2) requiring security upon which loans or advances of credit may be made;
(3) prescribing or limiting interest rates upon loans or advances of credit; or
(4) prescribing or limiting the period for which loans or advances of credit may be made;
does not apply to purchases, investments, or dispositions made under this section.