(b) Funds held in a fiduciary capacity by a depository institution, awaiting investment or distribution may, unless prohibited by the instrument creating the fiduciary relationship, be deposited in the commercial or savings or other department of the depository institution, provided that it shall first set aside under control of the trust department as collateral security, the classes of securities listed in G.S. 159-30(c) as being eligible for the investment of funds by local governments and public authorities equal in market value of such deposited funds, or readily marketable commercial bonds having not less than a recognized "A" rating equal to one hundred and twenty-five percent (125%) of the funds so deposited. The securities so deposited or securities substituted therefor as collateral in the trust department by the commercial or savings or other department (as well as the deposit of cash in the commercial or savings or other department by the trust department) shall be held pursuant to the provisions of G.S. 53-163.3.
If such funds are deposited in a depository institution insured under the provisions of the Federal Deposit Insurance Act, the above collateral security will be required only for that portion of uninvested balances of each trust which are not fully insured under the provisions of that act.