A series of decisions by all three levels of the New York State court system in BDC Finance L.L.C. v. Barclays Bank PLC, which culminated recently in a Court of Appeals decision remanding the case to the Supreme Court for trial, provides a window into the normally opaque world of collateral calls for over-the-counter derivatives transactions and offers some important lessons for hedge funds and other market participants.  In a guest article, Anne E. Beaumont, a partner at Friedman Kaplan Seiler & Adelman LLP, describes the factual background of the decisions, in particular, the relevant series of collateral calls; applicable law, contract language and market practice; the courts’ legal analyses in the relevant decisions; and three important lessons for hedge funds and other derivatives users.  For related analysis by Beaumont, see “Eighteen Major Banks Agree to Adopt FSB/ISDA Resolution Stay Protocol that Postpones Exercise of Right to Terminate Derivatives on Bank Counterparty Failure,” Hedge Fund Law Report, Vol. 7, No. 44 (Nov. 20, 2014); “The 1992 ISDA Master Agreement Says Notice Can Be Given Using an ‘Electronic Messaging System’; If You Think That Means ‘E-Mail,’ Think Again,” Hedge Fund Law Report, Vol. 7, No. 20 (May 23, 2014); and “Five Steps for Proactively Managing OTC Derivatives Documentation Risk,” Hedge Fund Law Report, Vol. 7, No. 16 (Apr. 25, 2014).