*408Order, Supreme Court, New York County (Richard B. Lowe, III, J.), entered January 25, 2006, which, in an action between plaintiff sponsor and defendant residential cooperative involving their respective rights to the building’s roof, granted defendant’s motions for summary judgment dismissing the complaint and declaring on its counterclaim that it is the owner of “any transferrable development rights” to the roof, modified, on the law, to deny defendant’s motion for summary judgment on its counterclaim, the above declaration vacated, and otherwise affirmed, without costs.
Defendant’s claim to the roof fails insofar as it is based on adverse possession because there is no evidence that defendant had ever claimed such right before September 1995, when it entered into the license agreement with Cellular Telephone Company (Cel-Tel), less than 10 years before the commencement of this action in October 2002 (see Ray v Beacon Hudson Mtn. Corp., 88 NY2d 154, 159 [1996]). Accordingly, we vacate the declaration that defendant is the owner of “any” transferable roof rights. However, defendant is entitled to summary judgment dismissing the complaint, which seeks past and future income from the Cel-Tel license agreement, based on its affirmative defenses of waiver and estoppel. In this regard, the record establishes that although plaintiff was represented on defendant’s Board, and indeed was in a position of Board leadership, during the time that the Cel-Tel license agreement and amendments adding antennas and increasing monthly fees were negotiated, discussed and executed, plaintiff never asserted the roof rights reserved for it in the 1986 offering plan until a February 2002 meeting of the Board. As it appears that the offering plan and its amendments were always in plaintiffs possession and thus readily available for plaintiff’s consultation and review, we find, as a matter of law, that plaintiff s failure to assert its right to the proceeds of the license agreement evinced a knowing intent not to claim such right (see General Motors Acceptance Corp. v Clifton-Fine Cent. School Dist., 85 NY2d 232, 236 [1995]). Contrary to the dissent, we do not find it persuasive that one of plaintiffs partners could not recall, and another *409partner was unaware, that plaintiff had retained the roof rights, particularly in light of plaintiffs February 14, 1985 certification submitted with the offering plan plainly stating, inter alia, that it had read the entire offering plan (cf. Baumann v Citizens Trust Co. of Binghamton, 248 App Div 9, 18 [1936], mod on other grounds 249 App Div 369 [1937], affd 276 NY 623 [1938]). Enforcement of the right to the proceeds of the license agreement at this juncture would also work an injustice on defendant, which, justifiably relying on plaintiffs forbearance, has been acting on the reasonable belief that such enforcement would not be sought (see Fundamental Portfolio Advisors, Inc. v Tocqueville Asset Mgt., L.P., 7 NY3d 96, 106 [2006]). Concur— Tom, J.P., Andrias, Marlow and Malone, JJ.