In September 2004, the global pharmaceutical manufacturer Merck & Co. removed Vioxx from the US market. The company soon faced almost 30,000 lawsuits over the alleged concealment of adverse effects. Despite suspicions that the Vioxx scandal would cripple the company's profitability, Merck's shares more than doubled between 2005 and 2007. Drawing on this case, I describe how scientific uncertainty surrounding the effects of Vioxx has been legally useful for Merck executives in exonerating their culpability for failing to disclose the adverse effects of the drugs. Extrapolating from this, I suggest uncertainty is generative and performative: it creates a demand for resolutions to the ambiguity it perpetuates, often strengthening the authority of those who have advanced a position of uncertainty to begin with. Finally, I argue paying more attention to the value of 'capitalized uncertainty' helps to nuance earlier work on the manufacture of risk and uncertainty.