Traditionally, American energy markets have been regulated using a combination of antitrust law and public utility law: the former has predominated in oil markets and the latter in markets for natural gas and electricity. Over time, energy markets have grown increasingly complex and competitive, due partly to changing market conditions (for example, in oil markets) and partly to regulation (in natural gas and electricity markets). Increasingly competitive energy markets meant increased risk for energy companies; those companies turned to energy derivatives as a way to hedge that risk. High energy prices and charges of manipulation in twenty-first century energy markets have led regulators to a new approach, one that borrows from securities regulation and focuses attention on “manipulation and deceit” by energy market participants. The securities model may be a bad fit for energy markets, however, because reliance on this new approach exposes consumers to price risks associated with the exercise of market power by sellers, risks to which buyers were not subject under traditional approaches to regulation. Specifically, the securities regulation model overlooks important ways in which sellers can exert market power at the expense of consumers in the absence of fraud or deceit. This is due to the way securities case law interprets the term “manipulation,” and to some regulators’ common assumptions about the ways in which market participants respond to price changes—assumptions that do not apply or apply only weakly in some energy markets. In this Article, we explore the origins of these “bad fit” problems, and examine their implications for the future of American energy markets.