Securities pledged pursuant to section 8-209 shall consist of any securities which constitute a legal investment for the trust company except for bills of exchange, notes, mortgages, banker's acceptances, or certificates of deposit. State, county, municipal, and corporate bond issues must be of investment quality and be rated in the three top categories of investment by at least one nationally recognized rating service, except that all issues of counties and municipalities of Nebraska shall be acceptable.

Such securities shall not be accepted for purpose of pledge at a rate above par value and if their market value is less than par value they shall not be accepted for such purpose above their actual market value. The safekeeping of such securities and all other expenses incidental to the pledging of such securities shall be at the expense of the trust company.