An insurer may invest in loans with a maturity not in excess of five years from the date thereof which are secured by pledge of securities eligible for investment under this chapter or by the pledge or assignment of life insurance policies issued by insurers authorized to transact insurance in this state. On the date made, no such loan shall exceed in amount 75 percent of the market value of the collateral pledged; except, that loans upon the pledge of United States government bonds and loans upon the pledge or assignment of life insurance policies shall not exceed 95 percent of the market value of the bonds or the cash surrender value of the policies pledged. The amount so loaned shall be included in the maximum amount of funds permitted under this chapter to be invested in a single person.