Except for contributions assessed for rate years 2021, 2022, 2023, 2024, and 2025, the contribution rate of each employer subject to contributions under RCW
50.24.010 shall include a solvency surcharge determined as follows:
(1) This section shall apply to employers' contributions for a rate year immediately following a cut-off date only if, on the cut-off date, the balance in the unemployment compensation fund is determined by the commissioner to be an amount that will provide fewer than seven months of unemployment benefits.
(2) The solvency surcharge shall be the lowest rate necessary, as determined by the commissioner, but not more than two-tenths of one percent, to provide revenue during the applicable rate year that will fund unemployment benefits for the number of months that is the difference between nine months and the number of months for which the balance in the unemployment compensation fund on the cut-off date will provide benefits.
(3) The basis for determining the number of months of unemployment benefits shall be the same basis used in RCW
50.29.025(1)(b)(i)(B).