(1) Thirty days after mailing a request for information to an employer regarding a predecessor-successor relationship, the department may determine if a predecessor-successor relationship exists based on the information available at that time.

(2) The department may send a letter to a predecessor or successor employer to determine a partial transfer of experience. A partial successor or predecessor employer must respond to the letter within thirty days of the mailing date. The response must show the percentage of operating assets transferred to the partial successor. Operating assets include the employees of the business.

(3) If the employer does not respond, the department may apply RCW 50.12.080 to determine necessary facts. In addition, for subsequent rate years the commissioner may estimate the percentage of operating assets transferred based on the best available information, which may include employment reports filed. That percentage will transfer to the successor until it provides compelling evidence to change the estimate. Any change in the estimate will be prospective only.