An insurer may invest any of the insurer's funds and accumulations in:
(1) an adequately secured equipment trust obligation or certificate or another adequately secured instrument evidencing:
(A) an interest in transportation equipment that is located wholly or partly within the United States; and
(B) a right to receive determined portions of rental, purchase, or other fixed obligatory payments for the use or purchase of the transportation equipment; and
(2) any other security as specifically authorized by law.