—Order, Supreme Court, New York County (Charles Ramos, J.), entered March 29, 1999, which granted defendants-respondents’ motions for summary judgment dismissing the complaint and for a default judgment on their counterclaims, unanimously affirmed, with costs.
On a motion for summary judgment, once the proponent has demonstrated, prima facie, entitlement to judgment as a matter of law, it becomes the burden of the opponent to present admissible evidence showing the existence of a triable issue of fact. Mere conclusions are insufficient to raise a triable issue of fact (Plantamura v Penske Truck Leasing, 246 AD2d 347, 348). Here, while defendants met their burden, plaintiff, in opposition, offered only self-serving conclusory assertions of breach of fiduciary duty, conversion, breach of contract and unjust enrichment. Nor did plaintiff show a reasonable excuse for its failure to timely reply to defendants’ counterclaims. Concur— Rosenberger, J. P., Ellerin, Rubin and Friedman, JJ.