(1) Except as provided in subsection (2) of this section, every loan or forbearance of money, goods, or thing in action shall bear interest at the rate of twelve percent per annum where no different rate is agreed to in writing between the parties: PROVIDED, That with regard to any transaction heretofore or hereafter entered into subject to this section, if an agreement in writing between the parties evidencing such transaction provides for the payment of money at the end of an agreed period of time or in installments over an agreed period of time, then such agreement shall constitute a writing for purposes of this section and satisfy the requirements thereof. The discounting of commercial paper, where the borrower makes himself or herself liable as maker, guarantor, or indorser, shall be considered as a loan for the purposes of this chapter.
(2)(a) Prejudgment interest charged or collected on medical debt, as defined in RCW
19.16.100, must not exceed nine percent.
(b) For any medical debt for which prejudgment interest has accrued or may be accruing as of July 28, 2019, no prejudgment interest in excess of nine percent shall accrue thereafter.
(3) A lease shall not be considered a loan or forbearance for the purposes of this chapter if:
(a) It constitutes a "consumer lease" as defined in RCW
63.10.020;
(b) It constitutes a lease-purchase agreement under chapter
63.19 RCW; or
(c) It would constitute such "consumer lease" but for the fact that:
(i) The lessee was not a natural person;
(ii) The lease was not primarily for personal, family, or household purposes; or
(iii) The total contractual obligation exceeded twenty-five thousand dollars.