Washington Revised Code Title 63. Personal Property § 63.30.380. Crediting income or gain to owner's account

If property other than money is delivered to the administrator, the owner is entitled to receive from the administrator income or gain realized or accrued on the property before the property is sold. If the property was an interest-bearing demand, savings, or time deposit, the administrator shall pay interest at the rate the property earned while in possession of the holder. Interest begins to accrue when the property is delivered to the administrator and ends on the earlier of the expiration of 10 years after its delivery or the date on which payment is made to the owner.