Wash. Rev. Code § 39.60.050
Notwithstanding the provisions of any other statute of the state of Washington to the contrary, it shall be lawful for any executor, administrator, guardian, or conservator, trustee or other fiduciary, to invest its funds or the moneys in its custody or possession, eligible for investment, in notes, bonds, or debentures of savings and loan associations, banks, mutual savings banks, savings and loan service corporations operating with approval of the federal home loan bank, and corporate mortgage companies: PROVIDED, That the notes, bonds or debentures are rated not less than "A" by a nationally recognized rating agency, or are insured or guaranteed by an agency of the federal government or by private insurer authorized to do business in the state: PROVIDED FURTHER, That the notes, bonds and debentures insured or guaranteed by a private insurer shall also be backed by a pool of mortgages equal to the amount of the notes, bonds or debentures.
RCW 39.60.050
Severability-1970 ex.s. c 93: "If any provision of this act, or its application to any person or circumstance is held invalid, the remainder of the act, or the application of the provision to other persons or circumstances is not affected." [ 1970 ex.s. c 93 s 4.]
Investment in local improvement district notes: RCW 35.45.150.