Delaware Code
Chapter 1. BOARD OF ACCOUNTANCY
§ 120. Ownership of working papers.

(a) All statements, records, schedules, working papers and memoranda made by a permit holder or a partner, shareholder, officer, director or employee of a permit holder, incident to or in the course of rendering services to a client, except the reports submitted by the permit holder to the client, and except for records that are part of the client's records, shall be and remain the property of the permit holder in the absence of an express agreement between the permit holder and the client to the contrary. No such statement, record, schedule, working paper or memorandum shall be sold, transferred or bequeathed without the consent of the client or the client's personal representative or assignee, to anyone other than 1 or more surviving partners or stockholders or new partners or stockholders of the permit holder or any combined or merged firm or successor in interest to the permit holder. Nothing in this section should be construed as prohibiting any temporary transfer of working papers or other material necessary in the course of carrying out quality reviews.
(b) A permit holder shall furnish to permit holder's client or former client, upon request and reasonable notice:

(1) A copy of the permit holder's working papers, to the extent that such working papers include records that would ordinarily constitute part of the client's records and are not otherwise available to the client; or
(2) Any accounting or other records belonging to or obtained from or on behalf of the client that the permit holder removed from the client's premises or received for the client's account; the permit holder may make and retain copies of such documents of the client when they form the basis for work done by the permit holder.
(c) Nothing herein shall require a permit holder to keep any working paper beyond the period prescribed in any other applicable statute.