—Mercure, J. Appeal from an order of the Supreme Court (Cardona, J.), entered April 30, 1992 in Albany County, which granted plaintiff’s motion for summary judgment.
Plaintiff brought this action against defendants Leslie V. Lowden, Jr. and Katherine E. Lowden (hereinafter collectively *775referred to as the Lowdens) to recover upon their written guarantee of indebtedness of defendant L. V. Lowden, Inc. Supreme Court granted plaintiff’s motion for summary judgment, defendants appeal and we now reverse.
Initially, we agree with defendants that the affidavits of plaintiff’s vice-president, Anthony Spensieri, Jr., failed to satisfy plaintiff’s initial burden of coming forward with prima facie evidence of the outstanding balance of the indebtedness. As this Court recently held, absent supporting documentary evidence or an explanation as to how the total amount of debt was calculated, "the conclusory allegations of plaintiff’s employees as to the total amount of outstanding debt arising out of plaintiff’s extensions of credit * * * are insufficient to satisfy [its initial] burden” (Transamerica Commercial Fin. Corp. v Matthews of Scotia, 178 AD2d 691, 694; see, Winegrad v New York Univ. Med. Ctr., 64 NY2d 851, 853; Zuckerman v City of New York, 49 NY2d 557, 562). Further, we conclude that defendants raised a factual issue concerning the Low-dens’ execution of the guarantees with their verified amended answer, wherein they "specifically [deny] the authenticity of the signatures on [the guarantees]” (see, CPLR 105 [t]; Bethlehem Steel Corp. v Solow, 51 NY2d 870, 872; National Sav. Bank v Hartmann, 179 AD2d 76, lv denied 79 NY2d 759).
Mikoll, J. P., Yesawich Jr., Crew III and Mahoney, JJ., concur. Ordered that the order is reversed, on the law, with costs, and motion denied.