ABSTRACT: Certification marks are conceived of by trademark law to be a specific kind of mark, used to denote that a product bearing it has been certified with respect to a given characteristic, such as material, mode of manufacture of goods or performance of services, quality, accuracy, and in some jurisdictions, geographical origin. As certification marks are intended to communicate something about the nature of the product bearing it, explicitly divorced from a product’s source, certification marks occupy a different role in the trademark law ecosystem as compared to trademarks. This paper explores how certification marks perform this certifying function. I argue that not all certification marks certify in the same way, and rather there are a range of certification marks that exist on a spectrum from those which fulfil their certifying function barely to robustly. I further argue that the significance of this spectrum reveals something about the ways that certification marks have the capacity to reduce information asymmetry in the market with respect to credence attributes. While often we may look to ways to make certification marks more rigorous badges of truthful information, I suggest our trademark law ecosystem may be better served by considering certification marks as vehicles of trust.