Wash. Rev. Code § 43.250.190
Funds placed in separately managed accounts pursuant to agreements between the office of the state treasurer and eligible governmental entities shall be invested and reinvested by the state treasurer so as to effectively maximize the yield to the separately managed account portfolios. In investing and reinvesting moneys in the separately managed accounts and in acquiring, retaining, managing, and disposing of investments of the separately managed accounts, there shall be exercised the judgment and care under the circumstances then prevailing which persons of prudence, discretion, and intelligence exercise in the management of their own affairs, not in regard to speculation but in regard to the permanent disposition of the funds considering the probable income as well as the probable safety of the capital. The state treasurer shall also consider the public policies of Washington and the values of its citizens when making investment-related decisions.
RCW 43.250.190