Fidelity won't comment on Abby's health. But over the past year, say several executives who have worked with her, she has appeared to have undergone medical treatment and lost her hair -- as well as weight from her already slim frame. Today she no longer wears a wig; her hair has grown back and she looks healthy. In keeping with her stoic reputation, she has rarely missed work. But since she has not uttered a word about her health, not even to senior colleagues, no one knows if there was even an illness.