Portfolio accounting systems and methods are adapted to handle uncertainty in accounting information due to time delay in information issuance. Accounting information is represented by streams of sequenced simple transaction states, each individual state describing the state of an account or its changes as known at a certain point in time while the stream ties the consecutive states into a life cycle of the information improving over time. A first simple transaction state attribute corresponds to the traditional value date. A second attribute corresponds to a reporting date. A third attribute corresponds to the traditional account value or relative/absolute changes thereof.