Users can model changes to entities in large scale sets of data for various portfolio holdings in different respective sandbox caches. A method includes loading, sets of data in a database and organizing the loaded data in entity caches according to an entity model, each entity cache corresponding to one or more entities associated with respective portfolio holdings. Further steps include creating an initial report of information drawn from the loaded data for manipulation by a user through a uses-interface, storing information in the initial report in a respective sandbox cache having data organized according to the entity model, and enabling the user to manipulate the respective sandbox cache to change values in the data organized according to the entity model in the respective sandbox cache without changing values of data in other sandbox caches or in the database.