Order unanimously affirmed without costs. Memorandum: The doctrine of waiver precludes an insurer from disclaiming coverage under an insurance policy where the insurer, with knowledge that there is a ground to void policy, nonetheless acts in recognition of the validity of the policy (see, Titus v. Glens Falls Ins. Co., 81 N.Y. 410, 419; Gilbert Frank Corp. v. Federal Ins. Co., 91 A.D.2d 31, 33-35, and cases cited therein). Applying that doctrine to this case, we find that Nationwide waived its right to disclaim when it participated in the intercompany property damage arbitration on behalf of its insured and conceded coverage of the offending vehicle. Thus, the court properly found the disclaimer invalid.