Any personal property or securities lawfully acquired by an insurer which it could not otherwise have invested in or loaned its funds upon at the time of such acquisition, shall be disposed of within 3 years from date of acquisition unless within such period the security has attained to the standard of eligibility; except, that any security or personal property acquired under any agreement of bulk reinsurance, merger or consolidation, may be retained for a longer period if so provided in the plan for such reinsurance, merger, or consolidation as approved by the superintendent under chapter 47. Upon application by the insurer and proof that forced sale of any such property or security would materially injure the interests of the insurer, the superintendent may extend the disposal period for an additional reasonable time. [PL 1973, c. 585, §12 (AMD).]