This is an action by the United States against Pro Football, Inc. (the Redskins) which operates the Washington Redskins professional football team. In its complaint the government alleged that the Redskins had violated the Economic Stabilization Act of 1970, as amended, 12 U.S.C. § 1904 note (Supp. Ill, 1974) (the Act, Executive Order 11723 (3A C.F.R. 184 (1973 Comp.)), and the regulations pursuant thereto, in charging ticket prices for two 1973 preseason games which exceeded the freeze base price. The government sought restitution by refunding overcharges to ticket purchasers, a civil penalty of $2,500 for each of the two games, and the costs of the litigation.
Following the Redskins’ answer and motions by both parties for summary judgment, the District Court for the District of Columbia, sua sponte, pursuant to § 211(c) of the Act, certified to the Temporary Emergency Court of Appeals as a substantial constitutional question the issue of whether application of Executive Order 11723 to the Redskins constituted “an ex post facto law, bill of attainder, a taking of property without just compensation, or a denial of due process of law.” Our court granted the government’s motion to have the entire case, both constitutional and non-constitutional issues, presented to us for final disposition. These, then, are the issues to be considered here:
(1) Whether the playing of football games at ticket prices higher than those charged in the 1972 season was a violation of the Economic Stabilization Act and Executive Order 11723;
(2) Whether it would be unconstitutional as an ex post facto law, bill of attainder, taking of property without *1398just compensation or a violation of the due process clause to apply Executive Order 11723 to the Redskins;
(3) Whether restitution should be ordered against the Redskins; and
(4) Whether civil penalties should be assessed against the Redskins.
ECONOMIC STABILIZATION PROGRAM
In order to understand the significance of the particular circumstances from which this case arose it is necessary first to briefly review the history of the economic stabilization program and its effect upon ticket prices for sporting events.
Section 203 of the Economic Stabilization Act authorizes the President to issue orders and regulations to “stabilize prices, rents, wages, and salaries at levels not less than those prevailing on May 25, 1970.” On August 15, 1971, the President exercised that authority in Executive Order 11615, 36 Fed.Reg. 15727 (1971), to impose a ninety-day freeze on prices, rents, wages and salaries (Phase I). Section 1 of the Order stabilized prices at levels not greater than those pertaining to transactions during a thirty-day period ending August 14, 1971. If no transactions occurred in that period then the ceiling would be established by the nearest preceding thirty-day period in which there were transactions. Section 1 of the Order further provided:
No person shall charge, assess, or receive, directly or indirectly in any transaction prices or rents in any form higher than those permitted hereunder, and no person shall, directly or indirectly, pay or agree to pay in any transaction wages or salaries in any form, or to use any means to obtain payment of wages and salaries in any form, higher than those permitted hereunder, whether by retroactive increase or otherwise.
The Order established a Cost of Living Council (COLC) to which was delegated most of the President’s authority under the Act. The Council was empowered to prescribe definitions for any terms used in the order, to make exceptions or grant exemptions, issue regulations and orders and to redelegate its authority to other federal agencies.
Under authority delegated by the COLC, the Director of the Office of Emergency Preparedness (OEP) issued circulars for general information. In order to explain the meaning of transaction as used in Executive Order 11615, OEP issued the following statement:
A transaction takes place when the seller ships the product to the buyer, not when the order is received. In the case of a service, the transaction takes place when the service is performed. Economic Stabilization Circular No. 101 § 302(1), 32A C.F.R. 40 (1974).
The OEP further provided:
The freeze applies to prices of advance sale tickets for sporting events occurring during the freeze. Economic Stabilization Circular No. 102 § 403(2), 32A C.F.R. 61 (1974).
Interpreting these Phase I guidelines, our court upheld the application of the rules to limit football ticket prices to those of the previous season where tickets were sold prior to the freeze for games to be played during the freeze. DeRieux v. Five Smiths, Inc., T.E.C.A., 499 F.2d 1321, cert. denied, 419 U.S. 896, 95 S.Ct. 176, 42 L.Ed.2d 141 (1974) (hereinafter Five Smiths ); University of Southern California v. Cost of Living Council, T.E.C.A., 472 F.2d 1065 (1972), cert. denied, 410 U.S. 928, 93 S.Ct. 1364, 35 L.Ed.2d 590 (1973) (hereinafter USC).
Phase II commenced November 13, 1971, and continued through January 12, 1973. The Price Commission was established to perform functions delegated to it by the COLC to stabilize rents and prices during this period of mandatory economic controls. During Phase II and continuing through Phase III the term “transaction” was redefined as occurring “at the time ... a binding contract is entered into between the parties,” rather than at the time of delivery of the services. Price Commission Regu*1399lations § 300.5, 6.C.F.R. 210 (1973). In a Phase II ruling on the question of advance sale of tickets the Price Commission held:
[T]he transaction occurs at the time the tickets are sold,- because the team is bound to supply the tickets to the given event and there has been consideration. . . . This definition of transaction is different from the definition of transaction in effect during the freeze which looked to the time goods were shipped or services were performed. . . . Price Commission Ruling 1972 — 73, 6 C.F.R. 349— 350 (1973).
On January 12, 1973, by Executive Order 11695, 38 Fed.Reg. 1473 (1973), the Phase III period of voluntary controls began. The Order abolished the Price Commission but continued the COLC which assumed the functions formerly performed by the Price Commission.
On June 15, 1973, the President issued Executive Order 11723, which froze prices for sixty days. Section 1 of the Order provided:
Section 1. Effective 9:00 p. m., e. s. t., June 13, 1973, no seller may charge to any class of purchaser and no purchaser may pay a price for any commodity or service which exceeds the freeze price charged for the same or a similar commodity or service in transactions with the same class of purchaser during the freeze base period. This order shall be effective for a maximum period of 60 days from the date hereof, until 11:59 p. m., e. s. t., August 12, 1973. It is not unlawful to charge or pay a price less than the freeze price and lower prices are encouraged.
Section 8 of the Order defined the “freeze base period” as the period from June 1 to June 8, 1973 or, for a seller who had no transactions during that period, the nearest preceding seven-day period in which he had a transaction. Section 8 further stated:
“Transaction” means an arms length sale between unrelated persons and is considered to occur at the time of shipment in the case of commodities and the time of performance in the case of services.
In order to clarify the application of Executive Order 11723 to the sale of tickets made in advance of the freeze for sporting events or other entertainment occurring during the freeze the COLC issued “Freeze Group Question and Answers No. 4,” 38 Fed.Reg. 16651 (1973), which included this response:
Admission prices for events occurring during the freeze period may be no higher than charges made for the same type of event which took place during the freeze base period. The price for advance tickets is deemed to be charged at the time of the performance of the entertainment or sporting event. If the ticket sales prior to the freeze were higher than the prices charged in a substantial number of transactions for the same type of event during the freeze base period, then reimbursement must be made in the amount a purchase was charged above the freeze price.1
Thus, the price freezes of 1971 and 1973 were designed to have the same effect on tickets to sporting events held during the freeze periods. The transaction was considered to occur, or the price was deemed to be charged, at the time of the playing of the game and it was as of that time that compliance with the freeze order was to be judged.
The question presented by this case is whether the particular circumstances under which the Redskins acted should serve to relieve them from the general application of this regulatory scheme.
*1400THE FACTS
The following facts were stipulated by the parties. In December 1972 the Price Commission authorized the Redskins, under Phase II of the price control program then in effect, to increase its ticket prices for the 1978 season by an average of $2.00 per ticket over 1972 prices in order to defray increased costs which the Commission found would be incurred in 1973. The Commission’s authorization was based on adequate disclosure by the Redskins of all relevant facts and was consistent with existing law.
On March 12, 1973, the Redskins increased ticket prices for games scheduled in 1973 by an average of $1.90 per ticket over 1972 prices. The specific price increases were as follows:
Number of
Seats 1972 Price 1973 Price
1,779 $12.00 $15.00
7,933 8.00 10.00
38,588 7.00 9.00
4,894 7.00 8.00
By the time these increases were made effective, the mandatory controls of Phase II had been replaced by the voluntary controls of Phase III.
By June 13, 1973, the beginning of the 1973 freeze period, the Redskins had sold most of the tickets for all of its scheduled 1973 home games except for the August 10 game with Denver. The Denver game had recently been rescheduled to be played in Washington, and only about twenty-five percent of the tickets for that game had been sold. Prior to the freeze the Redskins had substantially either expended or committed themselves to expend in their 1973 operations all of the proceeds of the increased ticket prices. The nature of the Redskins’ business is such that the cost of each season’s operations is substantially financed through the receipts in that same season.
During the period from June 13 to August 12, 1973, when the freeze was in effect, the Redskins played two home games, one on August 3 against Detroit and one on August 10 against Denver. For both of these games the Redskins charged the increased ticket prices set forth above. The amount of the increase for the two games was $180,-384.00.
Shortly before the playing of the August 3 game, the Redskins were advised that the Department of Justice felt that the ticket price increases for that game and the one to be played on August 10 were illegal because they exceeded those charged for the last game in 1972. The Redskins were further advised to inform purchasers at both games by public address announcements to retain their ticket stubs for possible refunds of excess prices. The Redskins agreed to make the announcements and did so at both games.
After the filing of this suit, the Redskins obtained the agreement of the Department of Justice to extend the time to answer in order to permit the Redskins to seek a determination by the COLC of the legality of the price increase. The Redskins’ request for exemption from the “transaction” definition of the 1973 freeze by the COLC was denied, as was a request for reconsideration. The Redskins then filed their answer in the litigation, claiming that the retroactive redefinition of “transaction” as applied to them and the retroactive reversal of the Price Commission’s approval of the price increases were invalid.
APPLICABILITY OF EXECUTIVE ORDER 11723 TO THE REDSKINS
The Redskins contend that the court should avoid the constitutional questions certified by construing Executive Order 11723 and the regulations pursuant thereto as inapplicable to them. They argüe that the Executive Order was not intended to reach those whose price increases had previously been approved by the Price Commission. However, by stating that a transaction occurs “at the time of performance in the case of services,” the Order clearly intended to invalidate price increases already *1401charged for performances scheduled to occur during the freeze period. There is no indication that the intent of the Order was to exempt increases which previously had been approved as appropriate to an earlier period of economic controls. Both the stipulation of the parties and a letter from the Redskins to the COLC indicate an understanding that the Price Commission had assured the Redskins only that an average ticket price increase of $2.00 would be within the limits of Phase II. The Redskins do not contend that they were ever assured that this authorization would immunize them from the effect of any later changes in the economic stabilization program. The ever-changing economy and the cascade of phases of the stabilization program would have made it clear to anyone that then-present controls could not be expected to remain stable for the indefinite future.
We, therefore, conclude that Executive Order 11723 was intended to limit ticket prices for all athletic events held during the freeze to prices charged during the base period. Since the base period for Redskins’ ticket sales was the 1972 season, it was a violation of the Order to charge prices higher than those in 1972 for the games held on August 3 and 10, 1973.
CONSTITUTIONALITY
Having concluded that Executive Order 11723 was applicable to the Redskins, we consider the question of whether that application was unconstitutional. The constitutional issue certified to our court by the district court is whether such application constituted “an ex post facto law, bill of attainder, a taking of property without just compensation, or a denial of due process of law.”
The questions of whether the government’s action represents a bill of attainder or a taking of property without just compensation, although included in the certification, were not raised by the Redskins in the district court and were not pursued in this proceeding. In any case, such arguments have been consistently rejected by our court. Five Smiths, supra, 499 F.2d at 1.334^1335, and cases cited therein. The ex post fac-to law and due process issues were raised by the Redskins in the district court and have been briefed and argued here.
Ex Post Facto Law. Article I, section 9 of the Constitution states, “No Bill of Attainder or ex post facto law shall be passed.” An ex post facto law is one which imposes a punishment for •an act which was not punishable at the time it was committed, or a punishment in addition to that then prescribed. Burgess v. Salmon, 97 U.S. 381, 384, 24 L.Ed. 1104 (1878). The Redskins contend that Executive Order 11723 is an ex post facto law insofar as it punishes them for selling tickets prior to the promulgation of Executive Order 11723 which made the higher prices illegal. They further argue that the government’s demand for restitution and civil penalties satisfies the element of punishment necessary to come within the ex post facto law prohibition. We need not reach this latter contention since we agree with the government that the act which was made illegal by the Order was not the selling of tickets prior to the Order’s issuance, but the failure to refund the excess prices prior to the games which were played at least seven weeks after the Order. Five Smiths, supra, 499 F.2d at 1335; USC, supra, 472 F.2d at 1069.
Due Process. The Redskins next contend that to apply Executive Order 11723 to them is retroactively to revoke the Price Commission’s approval of the price increases, an act which they argue is arbitrary and capricious and a violation of the Due Process Clause of the Constitution. As noted in the discussion of the ex post facto law and the cases cited therein, the transaction definition does not result in a retroactive application of controls.
The government’s actions of applying the Order to the Redskins and denying them an exemption from the transaction definition cannot be found to violate *1402substantive due process unless the actions were not reasonably calculated to effectuate the purposes of the Act and Order. The application of the transaction definition to football ticket prices has previously been upheld by our court in the face of similar challenges to its reasonableness. Five Smiths, supra; USC, supra.
The fact that a contract definition of transaction was utilized during the non-freeze periods of Phases II and III does not make use of a performance definition during a freeze period any less reasonable. USC, supra, 472 F.2d at 1072. As the COLC explained in its letter to the Redskins’ attorney denying the request for reconsideration, a contract definition would have the effect of freezing prices at a higher level. The Council determined that the economic situation of rapidly rising prices which existed pri- or to the 1973 freeze required imposition of a performance definition to maximally limit price increases. This determination was a reasonable one.
The Redskins, however, contend that the spiraling price increases did not result from increases approved during Phase II, but from those instituted during the Phase III “voluntary controls,” and so the freeze should have only affected the Phase III increases. Even ignoring the fact that the Redskins’ ticket price increases were not actually implemented until Phase III was underway, it was not irrational to apply a uniform rule to all athletic events occurring during the freeze regardless of whether the prices for advance tickets had been increased during Phase II or III. This is particularly true in view of the understanding by all parties that Phase II approvals were limited to assurances that increases were within Phase II guidelines and were not guarantees that the increases would be valid in some unknown future period.
RESTITUTION
Section 209 of the Act, as amended, empowers a court to order restitution of moneys received in violation of an order or regulation issued pursuant to the Act. Our court has previously ordered the refund of excess amounts paid for football tickets. Five Smiths, supra; USC, supra.
In view of the fact that the Redskins complied with the government’s request to announce at both games that spectators should retain their ticket stubs for a possible refund, it is appropriate to require the Redskins to make refunds only to those who can produce their ticket stubs. Refunds should be made to those purchasers in the amount the price paid for their tickets exceeded the price for the same seats charged during the 1972 season. We leave to the district court on remand to determine the administrative mechanism to be utilized for the payment of refunds, including such details as notification of purchasers and the time period during which ticket stubs may be presented for refunds.
At oral argument the government suggested that we order that any part of the $180,340.00 overcharge which is not refunded to ticket purchasers of the August 1973 football games be applied to reduce ticket prices during the 1975 football season. We need not reach the question of whether, in view of the expiration of the Economic Stabilization Act, our court would have the authority to order a prospective reduction of prices since, in any event, we believe that the circumstances of this case do not warrant such an order.
CIVIL PENALTIES
The government in its complaint and in this proceeding asks the court to impose against the Redskins the maximum civil penalty of $2,500 for each violation, or $5,000 for the two games. Section 208(b) of the Act and Section 7 of Executive Order 11723 authorize such a penalty for violations of orders or regulations.
The assessment of a civil penalty rests within the discretion of the court and, in *1403our view, this would be an inappropriate occasion for imposition of a penalty.
In light of the foregoing, the United States is entitled to judgment as a matter of law that the Redskins violated Executive Order 11723 in charging ticket prices in excess of the freeze base price for games played on August 3 and August 10, 1973. The ease is remanded to the district court with directions to enter judgment for the United States in accordance with this opinion and to implement the restitution ordered herein.
Remanded with directions.
. This release had the effect of giving the language of Executive Order 11723, to “charge . a price,” a meaning identical to the 1971 freeze language, to “charge ... in any transaction prices.”