
    Atlantic Mutual Insurance Co. et al., Respondents, v American Motorists Insurance Co., Appellant.
   — Order and judgment (one paper), Supreme Court, New York County (Edward Greenfield, J.), entered May 10, 1991, which denied defendant’s motion for summary judgment, granted plaintiffs’ cross-motion for summary judgment, and declared that defendant has a concurrent and equal duty as a co-insurer together with plaintiffs to defend its insureds in the underlying action and shall be responsible for twenty-five percent of all legal fees and expenses currently outstanding and to be incurred in the future in connection with the defense of the underlying action, unanimously affirmed, without costs.

As to the issue of defendant’s obligation to defend the underlying action, we affirm for the reasons stated by the IAS court. As to allocation of defense costs, we note that, as conceded by defendant at oral argument, the within policies provided successive, rather than concurrent, coverage to the insureds, and each insurer is therefore responsible for an equal share of defense costs (cf., North Riv. Ins. Co. v United Natl. Ins. Co., 172 AD2d 46). Concur — Murphy, P. J., Ellerin, Wallach and Smith, JJ.  