Differential argument marking (DAM) refers to case patterns where case-marking is conditioned by semantic properties of an argument. While the most well-known DAM patterns are those in which the argument with the relevant semantic property is the same argument that receives the marked case, there are also DAM patterns where a semantic property of one argument influences the case of another, including a little-known pattern in Ik where the person of the subject determines the case of the object. This paper shows that previous analyses of DAM do not address the full range of DAM phenomena, and offers a new analysis that can derive all of the DAM patterns as the result of valuation of unvalued interpretable features.