Regardless of whether certain letters exchanged between counsel constituted a binding stipulation disposing of the issues presented on appeal, the court providently exercised its discretion in denying the branch of plaintiffs motion which sought leave to amend the first amended complaint to add a claim under the New York City Human Rights Law, to the extent she *389sought leave to add a claim for punitive damages. Plaintiffs motion for leave to amend was made six years after the action was commenced, and after extensive discovery was finally complete. Plaintiff failed to offer any reasonable excuse for the extensive delay, which, with respect to the punitive damages claim, would have prejudiced defendant under the circumstances of the litigation (see Heller v Louis Provenzano, Inc., 303 AD2d 20 [2003]; see also Jablonski v County of Erie, 286 AD2d 927, 928 [2001]).
Under these circumstances, the Supreme Court likewise properly exercised its discretion in denying leave to supplement the complaint to assert additional causes of action based on new events (see Moon v Clear Channel Communications, 307 AD2d 628, 629-630 [2003]; Prince v O’Brien, 256 AD2d 208, 211-212 [1998]). Those claims can be determined in an independent action, if plaintiff chooses to file one, and we express no opinion on the merits of such claims. Concur—Saxe, J.P., Gonzalez, Buckley and Acosta, JJ.