To enhance our understanding of collusion in procurement settings, this paper quantitatively evaluates how the buyer's choice of a reserve price influences the sustainability of two previously devised collusive schemes. If the buyer does not select its reserve price strategically, then collusion may be sustainable for a wide range of plausible discount factors. However, even mildly sophisticated reserve price selection can dramatically shrink the set of discount factors for which collusion is sustainable. These findings support existing arguments that buyers are vulnerable to collusion, but they also suggest that buyers possess tools that may profitably induce sellers to act competitively.