A message may be used to update computing system of a commodity transaction. The message may include a commodity identifier, a date term, a quantity term, and a price term. The price term may include a formula arrangement or reference to a formula arrangement for calculating a fractional exposure of the entity to the commodity on each date in which an event affecting commodity transaction occurs. Each of these fractional exposures may be calculated for each commodity transaction and stored as separate entries in a data structure. The entries may then be updated, queried, and/or reorganized to generate an exposure position.