In this article I examine the properties of the pro module of Universal Grammar that are responsible for licensing null expletives. On the basis of facts from Hebrew, I argue that the features needed in order to identify a null subject may be assigned not only by Infl but from any phonologically discrete element in pro's CHAIN that bears?-features. This analysis thus lends support to Rizzi's (1986) dissociation of the formal licensing of pro and its identification.