We compare labor market outcomes under firm-level and sector-level bargaining in a one-sector Mortensen-Pissarides economy with firm-specific productivity shocks. Our main theoretical results are two-fold. First, unemployment is lower under firm-level bargaining, due both to a lower job destruction rate and a higher job-finding rate. Key to this result is the interplay between firm heterogeneity and wage compression under sector-level bargaining. Second, introducing efficient opting-out of sector-level agreements suffices to bring unemployment down to its level under decentralized bargaining. (C) 2012 Elsevier B.V. All rights reserved.