The provisions of this Part shall apply to all investments in debt and equity securities made by any savings bank pursuant to section 235.30 of the Banking Law, or by any savings and loan association pursuant to section 379.5 of the Banking Law. The provisions of this Part shall not apply to debt or equity securities acquired by a thrift institution in good faith in full or partial settlement, modification or readjustment of any investment made, pursuant to the Banking Law, by such thrift institution where the acquisition of such securities was necessary in order for the thrift institution to minimize or avoid loss in connection with such investment. Any thrift institution which makes an election (and notifies the department in writing of such election) to purchase securities pursuant to section 235.30 of the Banking Law and this Part shall not be authorized to purchase any securities pursuant to sections 235.1, 235.2, 235.3, 235.4, 235.5, 235.7, 235.7-a, 235.10, 235.11, 235.13, 235.14, 235.15, 235.19, 235.21(a)(2), 235.21(b), 235.21-a, 235.24, 235.24-a, 235.24-b, 235.24-c, 235.25, 235.26, 235.27 and 235.28-a of the Banking Law. No thrift institution which has purchased any security pursuant to section 235.30 of the Banking Law and this Part shall purchase any additional amount of such security pursuant to any other provision of the Banking Law. Any security which is not authorized for purchase by section 235.30 of the Banking Law may be purchased pursuant to the provisions of section 235.31 of the Banking Law. No thrift institution shall acquire any security pursuant to section 235.31 of the Banking Law if such acquisition would cause such institution to violate section 89.4 (excluding subdivisions [b] and [f] thereof) of this Part. The authority of a savings bank to make investments pursuant to sections 235.9(a)(6) and 235-d of the Banking Law, and the authority of a savings and loan association to make investments pursuant to sections 379-b and 381.1(e) of the Banking Law, is not affected by the enactment of this Part. Notwithstanding the foregoing, any security purchased by a thrift institution may be retained by such institution, provided that such security was legally acquired in compliance with the Banking Law.