Arizona Grocery Co. v. Atchison, Topeka & Santa Fe Railway Co
In Arizona Grocery Co. v. Atchison, Topeka & Santa Fe Railway Co., 284 U.S. 370 (1932), the Supreme Court held that the Interstate Commerce Commission could not order a common carrier to pay reparations for charging a rate that the agency had explicitly approved at the time it was collected, but subsequently determined to have been unreasonable.
In that case, the ICC had, in a proceeding described by the Court as "quasi-legislative," 284 U.S. at 388-89, ordered railroads shipping sugar from California to Phoenix, Arizona to charge no rate exceeding 96.5 cents per 100 pounds.
In response, the carriers adopted a rate of 86.5 cents, which they later reduced to 84 cents; these rates were then challenged before the Commission. In that proceeding, which the Court described as "quasi-judicial," id. at 389, the agency determined that this rate was unreasonable to the extent that it exceeded 71 to 73 cents and awarded the sugar shippers reparations from the carriers for the difference. The Supreme Court ultimately held that this damages award was improper:
Where the Commission has, upon complaint and after hearing, declared what is the maximum reasonable rate to be charged by a carrier, it may not at a later time, and upon the same or additional evidence as to the fact situation existing when its previous order was promulgated, by declaring its own finding as to reasonableness erroneous, subject a carrier which conformed thereto to the payment of reparation measuredby what the Commission now holds it should have decided in the earlier proceeding to be a reasonable rate. Id. at 390.