Arthur Zankel, who died yesterday at 73, was one of Wall Street’s leading investors, an important force in the Travelers-Citibank merger, and a philanthropist who initiated the building of Carnegie Hall’s widely heralded new performance space, the Judy and Arthur Zankel Hall.

As a co-managing partner of First Manhattan Company and managing partner of the REIT-trading High Rise Capital Management L.P., Zankel amassed a fortune said to be in excess of $1 billion, although he lived relatively modestly. He sat on the board of Citicorp until he retired in 2003, and also sat at various times on the boards of Primerica and Travelers, as well as those of Carnegie Hall, the Teacher’s College at Columbia, and Skidmore College.

Beginning in 1992, Zankel headed up the investment committee at Carnegie Hall and within a decade achieved a sevenfold increase in the hall’s endowment. While serving as vice chairman of Carnegie Hall, he donated $10 million to restore the hall to its original vision: a three-venue performance facility.

When it opened in 2003 with a concert featuring Yo-Yo Ma and Pierre Boulez, the $72 million, 644-seat hall, drilled out of Manhattan bedrock, was greeted with nearly unanimous praise, for both its acoustics and high-tech design.

At the time, Zankel told The New York Sun that he told the executive and artistic director of Carnegie Hall, Robert Harth, “I didn’t want to be able to recognize more than a few names on the program for the hall’s opening. The hall is designed to hit a more diverse audience, with a special emphasis on a younger crowd.”

According to the chairman of the board of Carnegie Hall, Sanford I. Weill, “One of the things that he loved about the hall that he helped to create was that it brought together artists from all over the world. We’ve done things with schools in New Delhi and Alaska. Music is really a universal language, and Zankel Hall gives Carnegie Hall the opportunity to present a lot of the cultures that make up this world.”

A native New Yorker whose father was a tie manufacturer, Zankel attend ed the University of Pennsylvania before earning an M.B.A. from Harvard Business School in 1955. He initially joined the investment firm of Hallgarten & Company, where he became a general partner. In 1965, he joined First Manhattan as a partner; in 1979, he became co-managing partner.

Zankel had a long association with Mr. Weill, chairman of the board at Citigroup. Mr. Weill appointed Zankel to the board of Travelers Group when he was CEO there, then brought him along to the Citigroup board after the merger in 1998.

“He was the director that really understood the numbers, would quickly be able to dissect the details of a transaction and could catch things that didn’t make a heck of a lot of sense,” Mr. Weill said yesterday.

Added Mr. Weill, “He was my best friend.”

An early investor in Berkshire Hathaway, Zankel had many business dealings with Warren Buffett. Zankel was widely respected on Wall Street for his number-crunching analytical abilities, activities more often the field of the young. His wildly successful High Rise Capital Management, where he generated gains of 41% in just two years, gave him special satisfaction for what was initially intended as a retirement activity.

He also served as mentor to a new generation of fund managers, who revered him for his knowledge and success – and also for a legendarily deadpan sense of humor, which he deployed with utter disregard to the eminence of the listener.

Zankel also oversaw investments for the Teachers College at Columbia and supported TC Reading Buddies at four Manhattan neighborhood schools. “If you look around the world, there is only democracy where there are minimal education standards,” Zankel said in an interview released by the college.

He also oversaw investments at Skidmore, where two of his sons attended college. The college awarded him an honorary doctor of laws degree, and he endowed a professorship for management.

In addition to an apartment on Fifth Avenue, Zankel maintained homes on Cape Cod and in Armonk, where he installed an indoor swimming pool in which he loved to exercise.

Arthur Zankel

Born February 16, 1932, in New York; died July 28 in New York, a presumed suicide; he was predeceased by his first wife, Nancy, in 1986, and is survived by his wife, Judy, and four sons from his first marriage, James, Mark, Thomas, and Kenneth.