This dissertation explores the speculative practices of blockchain entrepreneurs in South Korea following the 2017 Bitcoin investment frenzy. It defines speculation as a form of labor intended to navigate capitalism’s uncertainty and volatility. Rather than approach speculation as something to critique or disprove, it considers speculation as an analytical category to examineways in which speculation is an ethical, affective, and culturally situated practice, one that serves as a mode of self-fashioning and a way to generate meaning and structure, reproduce inequality, and pursue alternative possibilities. This ethnography contributes to broader conversations in anthropology around the place of speculation in everyday life. It joins a body of work that takes finance not as a discrete domain, but as a cultural force people deploy to imagine their futures and organize their lives. Building on scholarship in the anthropology of finance and neoliberalism, this dissertation showshow speculative logics are deeply personal, folded into people’s ambitions, affective worlds, and ethical projects. To address speculation as an ethical, affective, and culturally situated practice, the dissertation proposes the concept of speculation work. Challenging frameworks that separate speculative finance from the real economy, speculation work foregrounds the diverse ways in which these two domains are entwined and inseparable. I approach speculation work in terms of the relations between speculation and embeddedness: on the one hand, speculation is already an embedded practice as entrepreneurs draw on resources familiar to their contexts, histories, and circumstances. Meanwhile, entrepreneurs deploy these resources in unique and superabundant ways in attempts to generate and embed themselves into existing and emerging meanings andstructures. The chapters in this dissertation address how blockchain entrepreneurs draw on, manipulate, and deploy various resources to construct and situate themselves into contexts. Each chapter focuses on different resources – blockchain principles, neoliberal frameworks, chronotopes, economic and nation-building technologies – emphasizing a diversity in speculativepractices. Put together, they form an arc of speculation work with provisional effects, showing the contingent and fragile dimensions of capitalism, and shift towards speculation work with more enduring and committed outcomes, emphasizing more resilient dimensions of capitalism’s reproduction. By following blockchain entrepreneurs as they navigate uncertainty, imagine new futures, and attempt to bring them into being, this work foregrounds the inventive, diverse, and contingent ways in which capitalism is lived and remade on the ground.