Wash. Rev. Code § 11.100.037
Funds held by a bank or trust company in a fiduciary capacity awaiting investment or distribution shall not be held uninvested or undistributed any longer than is reasonable for the proper management of the account. These funds, including managing agency accounts, may, unless prohibited by the instrument creating the trust or by other statutes of this state, be deposited in the commercial or savings or other department of the bank or trust company, only if the bank or trust company first sets aside under control of the trust department as collateral security:
[ 1985 c 30 s 70. Prior: 1984 c 149 s 104; 1967 c 133 s 4. Formerly RCW 30.24.037.]
Short title—Application—Purpose—Severability—1985 c 30: See RCW 11.02.900 through 11.02.903.
Severability—Effective dates—1984 c 149: See notes following RCW 11.02.005.