Mr. Justice Holmes
delivered the opinion of the' Court.
This is a suit to reach and apply to a debt due from the Deutsche Bank Filiale to Humphrey money seized by the Alien Property Custodian and paid into' the Treasury of the United States. Humphrey, an American citizen, deposited money, payable on demand, in a German Bank in Germany, and demanded it, as the Courts have found, on or about June 12, 1915. The money was not paid, and this suit was begun oh July 9, 1921, under the Trading with the Enemy Act; October 6, 1917, c. 106; 40 St. 411. The debt was a debt of German marks. The Courts, below held that it should be translated into dollars at the rate of exchange existing.when the demand was made. 7 Fed. (2d) 330. The value of the mark fell after that daté and a writ of. certiorari was granted by this Court to determine whether the time fixed for the translation into dollars was correct. 269 U. S. 547.
In this case, unlike Hicks v. Guinness, 269 U. S. 71, at the date of the demand the German Bank owed no duty to the plaintiff under our law. It was not subject to our jurisdiction and the only liability that it incurred by its failure to pay was that which the German law'might impose. It has incurred no additional or othgr one since. A suit in this country is based upon an obligation existing under the foreign law at the time when the suit is brought, and the obligation is not enlarged by the fact that the creditor happens to be able to catch his debtor here. Davis v. Mills, 194 U. S. 451. See Western Union Telegraph Co. v. Brown, 234 U. S. 542. We may assume that when the Bank failed to pay on demand its liability was fixed at a certain number of marks both by the terms of the contract and by the German law — but we also assume that it was fixed in marks only, not at the extrinsic value that those marks then had in commodities or in the currency of another country. On the contrary, we repeat, it was and continued to be a liability in marks alone and was open to satisfaction by the payment of that number of marks, at any time, with whatever interest might have accrued, however much the mark might have fallen in value as compared with other things. See Société des Hôtels le Touquet Paris-Plage v. Cummings, (1922) 1 K. B. 451. An obligation in terms of the currency of a country takes the risk of currency fluctuations and whether creditor or debtor profits by the change the law takes no account of it. Legal Tender Cases, 12 Wall. 457, 548, 549. Obviously, in fact a dollar or a mark may have different values at different times but to the law that establishes it it is always the same. If the debt had been due here and the value of dollars had dropped before suit was brought the plaintiff could recover no more dollars on that account. A foreign debtor should be no worse off.
There has been so little discussion of what we regard as the principles that ought to govern this question that we refrain from citing-the many cases that have touched upon it and content oursélves with stating what seems to us the proper rule, only adding a few words as to Sutherland v. Mayer, 271 U. S. 272. That case conceméd the settlement of accounts of a German partnership having one member in America, and dealt with his claim to funds in America in the hands of the Boston branch until seized by the United States. With regard to the Boston partner's lien' upon that fund the partnership contract fairly might be regarded as subjecting the German partners to American law and warranting a settlement as of the date when it first became legal after the war, taking the mark at its value at that time. Hicks v. Guinness, 269 U. S. 71. It was held that in an equitablé proceeding where it was hard to lay down any logical rule substantial fairness warranted that result, referring to cases that arose after, the Civil War. Here we are lending our Courts to enforce an obligation (as we should put it, to pay damages;) arising from German law alone and ought to enforce no greáter . obligation than exists by that law at the moment when the suit is brought.
Decree reversed.'