What follows is an opinion from a United States Court of Appeals.
Intervenors who participated as parties at the courts of appeals should be counted as either appellants or respondents when it can be determined whose position they supported. For example, if there were two plaintiffs who lost in district court, appealed, and were joined by four intervenors who also asked the court of appeals to reverse the district court, the number of appellants should be coded as six.
When coding the detailed nature of participants, use your personal knowledge about the participants, if you are completely confident of the accuracy of your knowledge, even if the specific information is not in the opinion. For example, if "IBM" is listed as the appellant it could be classified as "clearly national or international in scope" even if the opinion did not indicate the scope of the business. 

Your task concerns the first listed appellant. The nature of this litigant falls into the category "private business (including criminal enterprises)", specifically "financial institution". Your task is to determine what subcategory of business best describes this litigant.

Opinion:
In the Matter of PENN CENTRAL TRANSPORTATION COMPANY, Debtor. Appeal of BANKERS TRUST COMPANY, in Nos. 78-1697 and 78-2313.
Nos. 78-1697 and 78-2313.
United States Court of Appeals, Third Circuit.
Argued Oct. 16 and 17, 1978.
Decided Jan. 11, 1979.
Donald M. Wilkinson, Jr., Robert W. Mannix, White & Case, New York City, for appellant Bankers Trust Co. as Indenture Trustee.
Charles A. Horsky, W. Crosby Roper, Jr., Brice M. Clagett, Washington, D. C., James E. Howard, John J. Ehlinger, Jr., Philadelphia, Pa., for the Trustees of Penn Central Transp. Co.; Covington & Burling, Philip R. Stansbury, Wesley S. Williams, Jr., Wynne M. Teel, Washington, D. C., Carl Helmetag, Jr., Philadelphia, Pa., of counsel.
Louis A. Craco, Willkie Farr & Gallagher, George J. Wade, Shearman & Sterling, New York City, for Citibank, N.A., as Agent for the Committee of Secured Bank Creditors; Walter H. Brown, Jr., Thomas L. Bryan, Michael B. Targoff, Richard L. Posen, Robert H. MacKinnon, Kenneth M. Kramer, New York City, of counsel.
Morris Raker, Sullivan & Worcester, Boston, Mass., for Richard Joyce Smith, Trustee of the Property of the New York, New Haven and Hartford Railroad Co., Debtor; Joseph Auerbach, Boston, Mass., of counsel.
Before GIBBONS and HIGGINBOTHAM, Circuit Judges.
Judge Aldisert heard argument in this appeal, which was consolidated with others, but did not participate in its decision.
OPINION OF THE COURT
PER CURIAM.
We deal herein with appeals filed by Bankers Trust Company, indenture trustee under the Consolidation Mortgage of June 20, 1913. For the reasons set forth in the opinions in Nos. 78-1698/1700, 78-1702/03, 78-1710, 78-2311/12, 78-2314/15, and 78-2319/20 3rd Cir., 596 F.2d 1127 filed simultaneously herewith, the orders confirming and consummating the Plan of Reorganization will be affirmed.

Question: This question concerns the first listed appellant. The nature of this litigant falls into the category "private business (including criminal enterprises)", specifically "financial institution". What subcategory of business best describes this litigant?

Choices:
bank
insurance
savings and loan
credit union
other pension fund
other financial institution or investment company
unclear

Answer: 5