Supplemental responses to interrogatories may be requested during litigation after the responses have been served. If considerable time and/or additional discovery has occurred, a party may ask another party to supplement their original responses with any additional information and/or responses. This type of request is referred to as “Supplemental Interrogatories.” This is not a separate category of interrogatory, but rather a request for supplemental or up-dated responses to the interrogatories (whether form or special) already served and responded to earlier in the discovery process.
California Code of Civil Procedure section 2030.070. (a) provides: ” In addition to the number of interrogatories permitted by Sections 2030.030 and 2030.040, a party may propound a supplemental interrogatory to elicit any later acquired information bearing on all answers previously made by any party in response to interrogatories.”
Sub-section (b) goes on to provide: “A party may propound a supplemental interrogatory 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), once after the initial setting of a trial date.”
More information regarding Supplemental Interrogatories can be found in the California Code of Civil Procedure.