Wash. Admin. Code § 284-18-385
If a domestic insurer, including any person controlling a domestic insurer, is proposing a merger or acquisition under RCW 48.31B.015(1)(a) that person must file a preacquisition notification form, Form E, set forth in WAC 284-18-950.
Additionally, if a nondomiciliary insurer authorized to do business in this state is proposing a merger or acquisition under RCW 48.31B.020 that person must file a preacquisition notification form, Form E. No preacquisition form need be filed if the acquisition is beyond the scope of RCW 48.31B.020 as set forth in RCW 48.31B.020(2)(b).
In addition to the information required by Form E, the commissioner may require an expert opinion as to the competitive impact of the proposed acquisition.
Wash. Admin. Code § 284-18-385