California Code, Financial Code - FIN § 14402

Every credit union may purchase and hold, either individually or jointly with other credit unions or affiliated organizations, a lot and building to be employed principally for the transaction of business, and to provide for future expansion of the facilities of those organizations.  Any excess space that is not occupied by the organizations purchasing and holding the building may be leased to the public.  The lot and building may be sold if all the holders of the property join in its sale.