A Cumulative Imbalance is the difference between supply and usage, and applies to noncore and core customers. Cumulative Imbalances may be resolved by trading with another Cumulative Imbalance, an Operating Imbalance, or a Storage Balance.

The imbalance at the end of the Trade Period must be within the 5% Tolerance Band to avoid cashout charges. Individual trades may move past zero by 3% of the imbalance month's usage.