William C. Dunham, as trustee of the Estate. of Robert L. Knetzer, bankrupt, brought this action to recover payments made to the defendants pursuant to the terms of an option to purchase real and personal property in Wyoming. The option was negotiated by Knetzer and was between the defendants and the Crandall Crеek Land and Cattle Company, a Wyoming corporation, which Knetzer organized and controlled. It was alleged that the trustee was the actual owner of any rights to recover the payments made on the option either by Knetzer or the corporation. The trial court held that the Crandall Creek Land and Cattle Company was an indispensable party and dismissed the action for lack of diversity. This appeal followed.
The defendants filed an answer to the originаl complaint. Thereafter, by order of court, the plaintiff was permitted to file *318 an amended complaint in which it was pleaded that on January 24, 1948, the defеndants entered into a written agreement with Knetzer giving him an option to purchase the ranch property in question; that Knetzer used the corporation as a device to handle and cover up his own activities as an individual, all of which was known to the defendants; that although the signature of Crandall Creek Land and Cаttle Company appears thereon, the option agreement was in fact between the bankrupt individually and the defendants; that the bankrupt was the beneficial owner of all rights under the option and furnished all the money paid to the defendants thereunder; and that the Crandall Creek Land and Cattle Company had аssigned to the trustee any and all right, title and interest of that corporation to the option, including the claim for a refund of the payments. 1
Attached to the оption was a contract of purchase which was to be executed if the option was exercised by the payment of $100,000 at its execution, and $50,000 on March 1st and June 1st, 1948. These payments were not made as required by the terms of the option. It is alleged, however, that Knetzer paid the defendants a total sum of $85,000 in various amounts and at various times other than the dates provided for in the option. The complaint alleges that on April. 12, 1948 defendants attempted to deсlare a forfeiture of the option agreement and all the sums paid thereon for failure to make the payments within the time provided for in the optiоn. A short time thereafter the property was sold to a third person. It is then alleged that the defendants, by their conduct, waived their right to insist upon strict complianсe with the terms of the option relating to time and amount of payments and to cancel the option and forfeit the payments without giving the bankrupt an oрportunity to cure the delinquency. It is conceded that if the Crandall Creek Land and Cattle Company is an indispensable party to the action that the trial court did not have jurisdiction. 2
In Choctaw and Chickasaw Nations v. Seitz, 10 Cir.,
Ordinarily whether parties are indispensable to an action should be determined by thе Federal Rules. 6 However, in a diversity case, where the rights of the party depend upon substantive law, then the law of the state prevails. 7
In Wyoming, as under the Fedеral Rules, actions must be prosecuted by the real party in interest. Wyo.Comp.Stat. 1945, 3-601; Fed.Rules Civil Proc. 17(a). It is not contended here that under Wyoming law the option оr a cause of action arising under it could not be assigned or that the assignee in such case could not maintain an action without joining the assignor. The genеral rule including Wyoming, is that if an assignment is full and complete and all the rights have been transferred, the assignee is the real party in interest. 8 The allegations here are to the effect that ¿11 the interest of the Crandall Creek Land and Cattle Company has been assigned to the trustee. The assignment is full and complete and rеgular on its face. It retains no interest to the corporation. The option contains no provision preventing assignment. The corporation very well may be a convenient and proper party to the action but it is not indispensable. *320 The defendants will have the right to make any defense against the clаim that they could make if the corporation were a party. The court may make a just determination of the claim of the trustee without in any way injuriously affеcting the rights, if any, of the corporation.
Judgment is reversed and the case remanded for further proceeding in accordance with the views expressed herein.
Notes
. The assignment reads:
“Know all men by these presents:
“That whereas on or about the 1st day of January, 1948, the Crandall Creek Land and Cattle Company and/or Robert L. Knetzer entered into a certain agreement with E. Y. Robertson and/or Mabel L. Robertson for the purchase of a certain ranch known as the ‘Hoodoo’ Ranch, and, at the time of the purchаse thereof, Robert L. Knetzer paid to the said E. V. Robertson and/or Mabel L. Robertson the sum of Eighty-five Thousand Dollars ($85,000); and
“Whereas said transaction regardless ■of the names used, was in reality a personal transaction of Robert L. Knetzer and had no connection with the Crandall Creek Land and Cattle Company, or Gеorge H. Allison, one of the principle stockholders thereof; and
“Whereas, William C. Dunham has duly been appointed Trustee in Bankruptcy of the bankrupt estаte of the said Robert L. Knetzer and has succeeded to all of the right, title and interest of the said Robert L. Knetzer.
“Now therefore, know all men by these presents that we the undersigned, the Crandall Creek Land and Cattle Company, by George H. Allison, its president, and Jerry W. Housel, its Secretary, and George H. Allison, individually, for and in considеration of the sum of One Dollar ($1.00) and other good and valuable consideration, the receipt of which is hereby acknowledged, do hereby sell, set ovеr, assign and convey to William C. Dunham, as Trustee of the bankrupt estate of Robert L. Knetzer, all of our right, title and interest in and to said agreement entered into between the Crandall Creek Land and Cattle Company and/or Robert L. Knetzer with E. V. Robertson and/or Mabel L. Robertson, including any and all right to any cause of action for refund or breach of contract in connection therewith.”
. Rule 19, Fed.Rules of Civil Procedure, 28 U.S.C.A. Webster v. Fall,
. Cyc.Fed.Proc. 3rd Ed., Vol. 6, Sec. 21.73; Niles-Bement-Pond Co. v. Iron Moulders Union,
. Words and Phrases, Perm.Ed., “Proper Party.” Baltimore & Ohio R. Co. v. Chicago River & Indiana R. Co., 7 Cir.,
. Words & Phrases, Perm.Ed., “Necessary Parties.” Cyc.Fed.Proc. 3rd Ed., Vol. 6, Sec. 21.73; American Auto. Ins. Co. v. Ryle, 5 Cir.,
. 3 Moore’s Fed.Practice, 2153, See. 19.07 (2 Ed.1948); Cowling v. Deep Vein Coal Co., 7 Cir.,
. Titus v. Wallick,
. Cyc.Fed.Proc., Vol. 6, 3rd Ed., Sec. 21.81; Fed.Prac. & Proc., Barron
&
Holtszoff, Vol. 2, Sec. 482; Larsen Sheep Co. v. Sjogren,
