Before revision: We formalize a cumulative interest compliant conservation requirement for pure financial products proposed by Wesseling and van den Bergh to make financial issues relating to these products amenable to mathematical analysis.
After revision: We develop an algebraic framework for the description and analysis of financial behaviours, that is, behaviours that consist of transferring certain amounts of money at planned times. To a large extent, analysis of financial products amounts to analysis of such behaviours. We formalize the cumulative interest compliant conservation requirement for pure financial products proposed by Wesseling and van den Bergh to make financial issues relating to these products amenable to mathematical analysis.