A bank may acquire, purchase, hold, and convey real and personal property for the following purposes only:
(1) that which is necessary for the convenient transaction of, or the promotion of, its business, including buildings containing banking offices, equipment, furniture and fixtures, art work, leasehold improvements, parking lots, and, with the prior approval of the department, real property reasonably anticipated to be necessary for future expansion of the bank, if the book asset value of the purchase or investment does not exceed 60 percent of the capital and surplus of the bank;
(2) the satisfaction of or on account of debts previously contracted in the course of its business;
(3) the purchase at sale under judgment, decree, lien, or mortgage foreclosure, against security held by it;
(4) that which is necessary in connection with a negatively amortizing loan described under AS 45.45.010(f).