California Code, Corporations Code - CORP § 7332

(a) A corporation may provide in its articles for one or more classes of memberships which are redeemable, in whole or in part, at the option of the corporation, or the member for such consideration within such time or upon the happening of one or more specified events and upon such terms and conditions as are stated in the articles.  However, no membership shall actually be redeemed if prohibited by Chapter 4 (commencing with Section 7410).

(b) Nothing in this section shall prevent a corporation from creating a sinking fund or similar provision for, or entering into an agreement for, the redemption or purchase of its memberships to the extent permitted by Chapter 4 (commencing with Section 7410).