The causes of the recent global financial crisis (GFC) have been the topic of intense debate, with commentators and others pointing to the enormous growth in, and relative lack of regulation of, derivative financial products, including over-the-counter equity swap agreements, as a contributing factor. In New Zealand the Court of Appeal held in Ithaca (Custodians) Ltd v. Perry Corporation [2004] 1 NZLR 731 that such swap agreements referencing substantial holdings in underlying securities of a particular company did not require disclosure under the substantial security holder disclosure provisions. This article analyses that decision in the context of the GFC and international regulatory trends, arguing that New Zealand’s provisions require reform.