Commercial scholarly publishers promote and sell bundles of journals—known as big deals—that provide access to entire collections rather than individual journals. Following this new model, size of serial collections in academic libraries increased almost fivefold from 1986 to 2011. Using data on library subscriptions and references made for a sample of North American universities, this study provides evidence that, while big deal bundles do decrease the mean price per subscribed journal, academic libraries receive less value for their investment. We find that university researchers cite only a fraction of journals purchased by their libraries, that this fraction is decreasing, and that the cost per cited journal has increased. These findings reveal how academic publishers use product differentiation and price strategies to increase sales and profits in the digital era, often at the expense of university and scientific stakeholders.