Cal. Unemployment Insurance Code § 1029

(a) Whenever an employer ceases to pay wages in employment, the reserve account of the employer, unless it has been transferred under Article 5 (commencing with Section 1051), shall be canceled on the records of the department after a period of three consecutive years has elapsed following the latest calendar quarter in which the employer paid wages in employment. (b) Whenever a period of three consecutive years has elapsed, commencing with the effective date of an election by any entity to finance benefits pursuant to Section 803, any portion of the reserve account of the entity that has not been subject to use pursuant to Section 712 or 713, unless that portion has been reacquired by the entity by termination of the election under Section 803 prior to the expiration of the three-year period, shall be canceled on the records of the department. Section 982 shall apply to that entity. (c) Upon the termination of an election by a school employer to finance benefits pursuant to Article 6 (commencing with Section 821) of Chapter 3, any favorable balance in the account of the school employer under the election shall be canceled on the records of the department.