It has been recently suggested that sponsor identification may be biased in favor of prominent brands. All things equal, consumers are more likely to attribute sponsorship to brands that they perceive to be more prominent in the marketplace, such as large-share brands. This article offers additional empirical evidence for this phenomenon and examines the underlying processes. The results of a controlled laboratory experiment replicate the phenomenon and show that this bias arises only when consumers are unable to retrieve the name of the sponsor directly from memory. In other words, direct retrieval is the default process of sponsor identification. The prominence bias is therefore more likely to occur in cluttered media environments where learning the event-sponsor associations is difficult. The findings further suggest that this bias emanates from a relatively controlled hypothesis-testing process that combines retrieval and constructive processes. During identification, the prominence of the brand is used as a confirmation cue that either validates or conflicts with people's vague recollections. The results also indicate that prominent brands identified or misidentified as sponsors do in fact benefit from enhanced brand image.