Wisconsin Statutes Civil Procedure (Ch. 799 to 847) § 804.08. Interrogatories to parties

(1) Availability; procedures for use. (a) Except as provided in s. 804.015, any party may serve upon any other party written interrogatories to be answered by the party served, or, if the party served is a public or private corporation or a limited liability company or a partnership or an association or a governmental agency or a state officer in an action arising out of the officer's performance of employment, by any officer or agent, who shall furnish such information as is available to the party. Interrogatories may, without leave of court, be served upon the plaintiff after commencement of the action and upon any other party with or after service of the summons and complaint upon that party.

(am) A party shall be limited, unless otherwise stipulated or ordered by the court in a manner consistent with s. 804.01(2), to a reasonable number of requests, not to exceed 25 interrogatories, including all subparts.

(b) Each interrogatory shall be answered separately and fully in writing under oath, unless it is objected to, in which event the reasons for objection shall be stated in lieu of an answer. The answers are to be signed by the person making them, and the objections signed by the attorney making them. The party upon whom the interrogatories have been served shall serve a copy of the answers, and objections if any, within 30 days after the service of the interrogatories, except that a defendant may serve answers or objections within 45 days after service of the summons and complaint upon that defendant. The court may allow a shorter or longer time. The party submitting the interrogatories may move for an order under s. 804.12(1) with respect to any objection to or other failure to answer an interrogatory.

(2) Scope: use at trial. (a) Interrogatories may relate to any matters which can be inquired into under s. 804.01(2), and the answers may be used to the extent permitted by chs. 901 to 911.

(b) An interrogatory otherwise proper is not necessarily objectionable merely because an answer to the interrogatory involves an opinion or contention that relates to fact or the application of law to fact, but the court may order that such an interrogatory need not be answered until after designated discovery has been completed or until a pretrial conference or other later time.