In the midst of the financial crisis, as bankers around the world worried about their fate, May Nasrallah made a bold decision. Having reluctantly agreed five years earlier to a request by Morgan Stanley’s John Mack to move to Dubai and set up an investment-banking hub for the U.S. company, she decided to resign. Not because she wanted to do less in the region. She wanted to do more. In 2010, she established a boutique advisory firm, deNovo, to work with wealthy clients in the Middle East. Nine years later, her decision is paying off.