Order, Supreme Court, New York County (Saralee Evans, J.), entered January 5, 2010, which granted defendant’s motion to dismiss pursuant to CPLR 3211, reversed, on the law, without costs, the motion denied and the complaint reinstated.
Initially, we note that on a CPLR 3211 motion to dismiss, “the court must afford the pleadings a liberal construction, take the allegations of the complaint as true and provide plaintiff the benefit of every possible inference” (EBC I, Inc. v Goldman, Sachs & Co., 5 NY3d 11, 19 [2005]).
Plaintiff is a partner at a large New York law firm and defendant is the deputy senior university director of labor relations at a university in New York. The parties married in 1973, separated in 2001, and were divorced during the summer of 2006. On June 27, 2006, they entered into an agreement to divide their property (hereinafter referred to as the agreement). Due to the length of their marriage, they agreed to an approximately equal division of marital property. They also agreed *402that property would be valued as of September 1, 2004 (hereinafter referred to as the cut-off date).
Plaintiff received the parties’ Scarsdale house and three of their automobiles; defendant received their Manhattan apartment (encumbered by a $370,000 mortgage) and an Audi. The parties agreed that each would keep accounts titled in his or her name. Plaintiff paid defendant $6,250,000 and transferred a further $368,000 to equalize the parties’ retirement accounts.
Each party acknowledged “that the property he or she is receiving or retaining pursuant to this Article represents a fair and reasonable share of the marital property.” The agreement contains mutual releases as well as a merger clause.
In the amended complaint, plaintiff alleges that at the time of their agreement the parties believed that they owned an account (hereinafter referred to as the Madoff Account) with Bernard L. Madoff Investment Securities which was their largest asset (purportedly $5.4 million as of the cut-off date). Of $6,618,000 that plaintiff paid defendant pursuant to the 2006 agreement, $2.7 million was attributable to defendant’s share of what the parties believed to be their $5.4 million Madoff Account. This account was titled in plaintiffs name. Plaintiff alleges that in reality, there was no such account because Madoff was running a Ponzi scheme.
In the parties’ agreement, plaintiff released, inter alia, “any and all claims to or upon the property of [defendant] . . . whether now owned or hereafter acquired or received, to the end that she shall have free and unrestricted right to dispose of her property now owned or hereafter acquired or received, free from any claim or demand of [plaintiff].” The releases in the parties’ agreement did not bar plaintiffs claims as a matter of law (see e.g. Littman v Magee, 54 AD3d 14, 15 [2008]).
Plaintiff pleads mutual mistake with the requisite particularity (see CPLR 3016 [b]; Pludeman v Northern Leasing Sys., Inc., 10 NY3d 486, 491 [2008]), and the amended complaint states a cause of action for reformation based on mutual mistake (see e.g. Banker v Banker, 56 AD3d 1105 [2008]; House v Wechsler, 104 App Div 124 [1905]). Contrary to defendant’s contention, mutual mistake can be based on a statement by a third party (see e.g. D'Antoni v Goff, 52 AD2d 973 [1976]; House, 104 App Div at 127). The cases cited by defendant where claims were dismissed pursuant to CPLR 3211 (a) (5) did not involve mutual mistake.
The documentary evidence proffered by defendant (see CPLR 3211 [a] [1]) does not utterly refute plaintiffs factual allegations or conclusively establish a defense as a matter of law (see *403e.g. McCully v Jersey Partners, Inc., 60 AD3d 562 [2009]). With respect to the branch of defendant’s motion based upon CPLR 3211 (a) (7), even though defendant submitted documents, “dismissal should not eventuate” unless she shows that a material fact alleged by plaintiff “is not a fact at all and unless it can be said that no significant dispute exists regarding it” (Guggenheimer v Ginzburg, 43 NY2d 268, 275 [1977]). Such is not the case here.
The motion court and the dissent both err in relying on the claim — which was not in defendant’s affidavit — that, for several years after the parties’ agreement, plaintiff could have redeemed what the parties believed to be their account for cash in excess of its supposed value as of the cut-off date selected by the parties (see e.g. Rovello v Orofino Realty Co., 40 NY2d 633, 636 [1976]). Both the motion court and the dissent also err by resolving a fact — the assumption on which the parties relied in dividing their property — in defendant’s favor on a motion to dismiss (see Viskovich v Walsh-Fuller-Slattery, 16 AD2d 67 [1962], affd 13 NY2d 1100 [1963] [trial was held when the plaintiff alleged that state of facts assumed to exist at time of the parties’ agreement did not, in fact, exist]).
Indeed, the dissent speculates as to plaintiffs expectations that the “Madoff account. . . continue its highly profitable performance” and asserts “[accordingly, he alone took on the risk that he might not be able to recoup his investment” citing Reiss v Financial Performance Corp. (97 NY2d 195, 201 [2001]).
A couple of observations are in order. First, in the context of a CPLR 3211 motion, plaintiffs motivations as alleged by defendant are irrelevant because the allegations in the amended complaint must be accepted as true. Second, Reiss is a declaratory injunction action concerning a stock swap; no allegation of mutual mistake is present.
Further, even though there is an express contract between the parties, it is unclear whether it covers the current dispute; therefore, plaintiff may plead unjust enrichment (see e.g. IIG Capital LLC v Archipelago, L.L.C., 36 AD 3d 401, 405 [2007]), and the amended complaint states such a cause of action (see Simonds v Simonds, 45 NY2d 233, 242 [1978]).
Finally, defendant and the dissent ignore the allegations of mutual mistake as to the actual existence of the account itself. Both defendant and the dissent attempt to foreclose plaintiffs claims by transmogrifying the claim of mutual mistake into a claim of mistake in valuation.
The dissent states: “[a]t the time of the agreement, Steven had an account in his name with [Madoff].” Untrue. Steven *404never had an account in his name with Madoff; on Madoffs own admission there were no accounts within which trades were made on behalf of investors.
The dissent then states, “Steven liquidated part of the account to fund his payments to Laura.” Untrue. In Madoffs Ponzi scheme what appeared to Steven and Laura to be a partial liquidation of an account was simply a payment to Steven that came from funds deposited by a more recent “investor” in what the “investor” believed was his own account.
The dissent further observes, “[Steven] did not liquidate the rest of the Madoff account . . . and he continued to invest in it.” Untrue. There was no account which could be liquidated, as became apparent when Madoff received $7 billion worth of “liquidation” calls from investors in 2008. Nor was Steven “investing” in an account; his further contributions went directly to pay other “investors” in the scheme. Concur — Tom, Andrias and Catterson, JJ.