We use an extended version of the well-established Crepon, Duguet, and Mairesse model [1998. "Research, Innovation and Productivity: An Econometric Analysis at the Firm Level." Economics of Innovation and New Technology 7 (2): 115-158] to model the relationship between appropriability mechanisms, innovation, and firm-level productivity. We enrich this model in three ways: (1) We compare estimates obtained using a broader definition of innovation spending to those that use R&D spending. (2) We assume that a firm simultaneously innovates and chooses among different appropriability methods to protect the innovation. (3) We estimate the impact of innovation output on firm productivity conditional on the choice of appropriability mechanism. We find that firms that innovate and rate formal methods for the protection of intellectual property highly are more productive than other firms, but that the same does not hold in the case of informal methods of protection, except possibly for large firms as opposed to SMEs. We also find that this result is strongest for firms in the services, trade, and utility sectors, and negative in the manufacturing sector.ARTICLE HISTORY