In the field of business and politics, research on the role of business actors in individual fossil fuel industries that contribute to climate change has been sparse. At the same time theorising the role of ad hoc coalitions has been limited even though they appear to be an important vehicle for business actors seeking to shape contemporary policy contests. This paper attempts to address these understudied areas by drawing on a rich empirical dataset to examine the role of three ad hoc coalitions in the U.S. energy sector. In doing so, it builds on the existing literature to establish a theoretical basis for identifying the defining elements of ad hoc coalitions and the conditions under which business actors decide to establish them. Further, it sheds light on how business actors use ad hoc coalitions in three key fossil fuel industries - gas, oil, and coal - to shape policy outcomes, and in turn shape the path to a clean energy transition.