Balance Roll-Forward

A balance roll-forward explains how an opening balance becomes a closing balance through movements during a specified interval. Define the account, population, currency, sign convention, and time boundaries before adding values. Compare the calculated closing balance with an independently supplied closing observation.

For a simplified prepaid wallet, opening 100 USD plus issuance 50 minus redemption 30 gives an expected closing balance of 120 USD. Refunds, expiry, and adjustments need separate terms when they exist. The movement categories must be complete and non-overlapping; a balancing adjustment created only to make the equation pass hides the unresolved difference.

Equal aggregate balances can hide misallocation. If card A is overstated by 1 USD and card B understated by 1 USD, the total difference is zero while both card records are wrong. Compare by stable card identity as well as in total, and investigate movements whose card is absent from the register. Deduplicate by movement identity rather than by equal amounts.

Align the opening and closing snapshots with the same movement interval and retain the information cutoff used for each report. The equation tests a relationship, not revenue recognition or the quality of two sources sharing the same error. An operational expiry movement is not by itself an instruction to recognize revenue.

See Integrating Payment, Commerce, and Finance Data for worked examples.