California Code, Business and Professions Code - BPC § 6103.5

(a) A licensee of the State Bar shall promptly communicate to the licensee's client all amounts, terms, and conditions of any written offer of settlement made by or on behalf of an opposing party. As used in this section, “client” includes any person employing the licensee of the State Bar who possesses the authority to accept an offer of settlement, or in a class action, who is a representative of the class.

(b) Any written offer of settlement or any required communication of a settlement offer, as described in subdivision (a), shall be discoverable by either party in any action in which the existence or communication of the offer of settlement is an issue before the trier of fact.