Cal. Bus. & Prof. Code § 16601
Any person who sells the goodwill of a business, or any owner of a business entity selling or otherwise disposing of all of his or her ownership interest in the business entity, or any owner of a business entity that sells (a) all or substantially all of its operating assets together with the goodwill of the business entity, (b) all or substantially all of the operating assets of a division or a subsidiary of the business entity together with the goodwill of that division or subsidiary, or (c) all of the ownership interest of any subsidiary, may agree with the buyer to refrain from carrying on a similar business within a specified geographic area in which the business so sold, or that of the business entity, division, or subsidiary has been carried on, so long as the buyer, or any person deriving title to the goodwill or ownership interest from the buyer, carries on a like business therein.
For the purposes of this section, "business entity" means any partnership (including a limited partnership or a limited liability partnership), limited liability company (including a series of a limited liability company formed under the laws of a jurisdiction that recognizes such a series), or corporation.
For the purposes of this section, "owner of a business entity" means any partner, in the case of a business entity that is a partnership (including a limited partnership or a limited liability partnership), or any member, in the case of a business entity that is a limited liability company (including a series of a limited liability company formed under the laws of a jurisdiction that recognizes such a series), or any owner of capital stock, in the case of a business entity that is a corporation.
For the purposes of this section, "ownership interest" means a partnership interest, in the case of a business entity that is a partnership (including a limited partnership a limited liability partnership), a membership interest, in the case of a business entity that is a limited liability company (including a series of a limited liability company formed under the laws of a jurisdiction that recognizes such a series), or a capital stockholder, in the case of a business entity that is a corporation.
For the purposes of this section, "subsidiary" means any business entity over which the selling business entity has voting control or from which the selling business entity has a right to receive a majority share of distributions upon dissolution or other liquidation of the business entity (or has both voting control and a right to receive these distributions.)
Ca. Bus. and Prof'l. Code § 16601