A General Rate Increase (GRI) is an adjustment to shipping rates that ocean carriers can implement at their discretion. U.S. regulations require that any GRI be announced at least 30 days in advance. As a result, carriers in the U.S. typically announce these increases on the first of the month, with the new rates taking effect on the first day of the following month. The amount of the GRI can fluctuate significantly from month to month and may differ among carriers and trade routes.