Now: Cruz took the fall after Morgan Stanley sustained a $4 billion trading loss on a bad mortgage bet. "I found it devastating," Cruz told Fortune. "I entertained the idea of going back to school and becoming an architect," she says. But recognizing where her skills lie -- in assessing investment risk around the world -- last year Cruz started started her own firm: Voras Capital Management, a hedge fund named after the mountainous region in Greece where she was born.
"We're operating profitably," says Cruz, now 55 and a mother of three. Her outlook on the markets? "Despite extreme volatility, I don't subscribe to the double-dip theory in the U.S. I'm optimistic."
By Patricia Sellers
NEXT: Ed de Castro