Rule 33.Interrogatories to Parties.

Subdivision (a) lets any party serve written interrogatories on any other party. An entity answers through an officer or agent, who must furnish the information available to the party, not only what that individual happens to know. Interrogatories may be served after the action starts and without leave of court, with one exception: if the plaintiff serves them within twenty days after service upon the defendant, leave of court, with or without notice, must be obtained first.

The answering rules are strict about form. Each interrogatory is answered separately and fully in writing under oath, each answer is preceded by the interrogatory it responds to, and the person making the answers signs them. Copies of the answers and objections go to the other side within forty days after service of the interrogatories, unless the court on motion and notice and for good cause shown enlarges or shortens that time. Specific written objections travel with the answers and must state the grounds they rest on, and the party still answers everything that is not objectionable. Failure to serve objections waives them. Answers to interrogatories under objection may be deferred until the court enters an order to answer under Rule 37(a), and an objection or motion made without substantial justification exposes the maker to the sanctions in Rule 37(a).

Subdivision (b) sets the reach and the cap. Interrogatories may relate to anything that can be inquired into under Rule 26(b), and they may be served before or after a deposition of the same person. The number is the part people miss: no more than one set on a party, and no more than thirty interrogatories in total, unless the court orders otherwise for good cause shown. A question is not objectionable merely because it calls for an opinion or a contention relating to fact, or to the application of law to fact, though the court may order that it need not be answered until other designated discovery is done.

Subdivision (c) sets a deadline that arrives near trial. A party who later obtains information rendering its answers incomplete or incorrect must serve amended answers no later than ten days before the day fixed for trial; after that, amendment takes a motion and whatever terms the court directs. Subdivision (d) offers a way out of a burdensome question: where the answer may be derived from business records and the burden of deriving it is substantially the same for both sides, the responding party may specify the records in enough detail for the other party to locate the answer as readily, and afford a reasonable opportunity to examine, audit, inspect and copy them.