N.Y. Comp. Codes R. & Regs. tit. 11 § 216.11
To verify compliance with this Part and related statutes, Department of Financial Services examiners will investigate the market performance of insurers. To enable department personnel to reconstruct an insurer's activities, all insurers subject to the provisions of this Part must maintain within each claim file all communications, transactions, notes and work papers relating to the claim. All communications and transactions, whether written or oral, emanating from or received by the insurer shall be dated by the insurer. Claim files must be so maintained that all events relating to a claim can be reconstructed by the Department of Financial Services examiners. Insurers shall either make a notation in the file or retain a copy of all forms mailed to claimants.
N.Y. Comp. Codes R. & Regs. Tit. 11 § 216.11