Cal. Civ. Proc. Code § 2016.090

(a) The following shall apply in a civil action unless modified by stipulation by all parties to the action: (1) Within 60 days of a demand by any party to the action, each party that has appeared in the action, including the party that made the demand, shall provide to the other parties an initial disclosure that includes all of the following information: (A) The names, addresses, telephone numbers, and email addresses of all persons likely to have discoverable information, along with the subjects of that information, that the disclosing party may use to support its claims or defenses, or that is relevant to the subject matter of the action or the order on any motion made in that action, unless the use would be solely for impeachment. The disclosure required by this subparagraph is not required to include persons who are expert trial witnesses or are retained as consultants who may later be designated as expert trial witnesses, as that term is described in Chapter 18 (commencing with Section 2034.010) of Title 4 of Part 4. (B) A copy, or a description by category and location, of all documents, electronically stored information, and tangible things that the disclosing party has in its possession, custody, or control and may use to support its claims or defenses, or that is relevant to the subject matter of the action or the order on any motion made in that action, unless the use would be solely for impeachment. (C) Any contractual agreement and any insurance policy under which an insurance company may be liable to satisfy, in whole or in part, a judgment entered in the action or to indemnify or reimburse for payments made to satisfy the judgment. (D) Any and all contractual agreements and any and all insurance policies under which a person, as defined in Section 175 of the Evidence Code, may be liable to satisfy, in whole or in part, a judgment entered in the action or to indemnify or reimburse for payments made to satisfy the judgment. Only those provisions of an agreement that are material to the terms of the insurance, indemnification, or reimbursement are required to be included in the initial disclosure. Material provisions include, but are not limited to, the identities of parties to the agreement, the nature and limits of the coverage, and any and all documents regarding whether any insurance carrier is disputing the agreement’s or policy’s coverage of the claim involved in the action. (2) A party shall make its initial disclosures based on the information then reasonably available to it. A party is not excused from making its initial disclosures because it has not fully investigated the case, because it challenges the sufficiency of another party’s disclosures, or because another party has not made its disclosures. (3) (A) A party that has made, or responded to, a demand for an initial disclosure pursuant to paragraph (1) may propound a supplemental demand on any other party to elicit any later-acquired information bearing on all disclosures previously made by any party. (B) A party may propound a supplemental demand twice before the initial setting of a trial date, and, subject to the time limits on discovery proceedings and motions provided in Chapter 8 (commencing with Section 2024.010) of Title 4 of Part 4, once after the initial setting of a trial date. (C) Notwithstanding subparagraphs (A) and (B), on motion, for good cause shown, the court may grant leave to a party to propound one additional supplemental demand. (4) A party’s obligations under this section may be enforced by a court on its own motion or the motion of a party to compel disclosure. (5) A party’s disclosures under this section shall be verified either in a written declaration by the party or the party’s authorized representative, or signed by the party’s counsel.

(b) Notwithstanding subdivision (a), this section does not apply to the following actions: (1) An unlawful detainer action, as defined in Section 1161. (2) An action in the small claims division of a court, as defined in Section 116.210. (3) An action or proceeding commenced in whole or in part under the Family Code. (4) An action or proceeding commenced in whole or in part under the Probate Code. (5) An action in which a party has been granted preference pursuant to Section 36.