Tools for managing systems requirements help keeping specifications consistent, up-to-date and accessible. Since the requirements for complex systems are themselves complex information structures that must be handled in complex process scenarios, there are many strong requirements concerning a tool for managing them. This work presents a requirements catalog for requirements management tools that is based on substantial project experience (including tool evaluation experiences) in the area of automotive as well as aircraft and defense systems. The purpose of this catalog is to help users compare and select requirements management tools as well as helping tool providers to direct future tool developments.