Orders, Supreme Court, New York County (Peter Tom, J.), entered June 17, 1992 and July 29,1992, which, inter alia, in an action for foreclosure, granted plaintiff’s motion for summary judgment, and, upon reargument, adhered to that determination, unanimously affirmed, with costs.
*398Defendant Ward Equities (Ward) asserts that it was fraudulently induced into entering into the subject mortgage by plaintiff Friesch-Groningsche Hypotheekbank Realty Credit Corporation’s (FGH) repeated oral promises not to foreclose on its $12.5 million loan to Ward if the commercial tenancies in the mortgaged building were terminated. Although paragraph G of the parties’ agreement requiring any changes to be in writing would generally preclude any such oral modification (see, General Obligations Law § 15-301 [1]), to the extent that a mortgagee makes promises in bad faith, on which the mortgagor relies to his or her detriment, the mortgagee can be equitably estopped from foreclosing on the mortgage (see, Nassau Trust Co. v Montrose Concrete Prods. Corp., 56 NY2d 175, 183). Here, however, Ward offers only unsubstantiated allegations that the oral modification was reached and that defendant Slabakis relied on FGH’s promises in entering into the mortgage and in extending a personal guaranty of repayment. Since Ward failed to come forward with evidentiary proof sufficient to raise an issue as to a defense to payment on the loan instrument, FGH is entitled to summary judgment of foreclosure (see, Interman Indus. Prods. v R. S. M. Electron Power, 37 NY2d 151, 155). Furthermore, we agree with the IAS Court that the contention of defendant Slabakis, an experienced real estate investor, that a modification of a $12.5 million mortgage was reached without a written memorialization thereof, fails to meet the "threshold of believability” of an oral promise to forego or delay foreclosure (New York State Urban Dev. Corp. v Marcus Garvey Brownstone Houses, 98 AD2d 767, 771). Concur — Sullivan, J. P., Ellerin, Wallach, Kupferman and Ross, JJ.