California Code, Business and Professions Code - BPC § 25512

(a) Notwithstanding any other provision of this division, any licensee or officer, director, employee, or agent of a licensee that holds no more than eight on-sale licenses may also hold not more than 16.67 percent of the stock of a corporation that holds a Type 01 or Type 23 beer manufacturer license as specified insubdivision (b) of Section 23320 that are located in Sacramento, Placer, Contra Costa, San Joaquin, or Napa County, and may serve on the board of directors and as an officer or employee of that corporate licensed beer manufacturer.

(b) An on-sale licensee specified in subdivision (a) shall purchase no alcoholic beverages for sale in this state other than from a licensed wholesaler or winegrower.

(c) In enacting this section, the Legislature finds that it is necessary and proper to require a separation between manufacturing interests, wholesale interests, and retail interests in the production and distribution of alcoholic beverages in order to prevent suppliers from dominating local markets through vertical integration and to prevent excessive sales of alcoholic beverages produced by overly aggressive marketing techniques. The Legislature further finds that the exception established by this section to the general prohibition against tied-house interests must be limited to its expressed terms so as not to undermine the general prohibition, and intends that this section be construed accordingly.