For many people, investment banking is just a job where you can make good money. For David Winton, banking was a practically a calling.

As an undergraduate at Fordham University's business school, Mr. Winton was the chief executive of the student-run federal credit union. He recruited his roommate Gregory Moundas to be president, and, volunteering 30 hours a week, the two of them turned around a troubled institution and doubled its assets in two years, Mr. Moundas said. Even as Mr. Winton rose to vice president at Keefe, Bruyette & Woods, where he was a research analyst, he made frequent trips back to Fordham to be on the student bank's supervisory committee.

Mr. Winton, 29, inherited some of his head for finance from his mother, a retired bank officer. But Mr. Moundas said a lot of his friend's ardor for banking grew out of a protective love for his family.

"His father died when he was in high school and he wanted to provide for his mom and his sister," Mr. Moundas said. "He never really talked about it, but that was one of the things that really motivated him."

On weekends, Mr. Winton frequently made the two-hour trip from Brooklyn Heights to his mother's house near Hartford, usually taking along his fiancée (they were to be married Nov. 17).

"After we lost his father, he said, `I'll never leave you, Mom,' " Joan Winton said. "He never did."