It's commonly argued that business puts women in a no-win situation: If they're tough and demanding, they're labeled with words that rhyme with "rich." If they're consensus-builders, they get tagged as "soft." It's interesting, then, that the last line of the New York Times' examination of Zoe Cruz's rise and fall at Morgan Stanley is this: "Did her status as a demanding woman in a male-dominated industry tip the scales against her, they wonder," with "they" being Cruz's supporters.

Last week, Cruz was ousted from her role as Morgan Stanley's co-president. Billions in trading losses from investments related to sub-prime credit. were laid at her feet. As The Wall Street Journal notes, her management style and past political maneuverings also played their roles in pushing her toward the door.

Like her style or not, Cruz's departure continues a trend of thinning ranks among top women executives on Wall Street, the Times says. "At Citigroup, Sallie L. Krawcheck, once seen as a successor to (Charles) Prince, was recently moved from the job of chief financial officer to running the firm’s brokerage division and she is no longer considered a candidate to run Citigroup." And, the paper notes, "with Ms. Cruz no longer a candidate to run Morgan Stanley, the top executive ranks at the big Wall Street firms remain largely devoid of women seen with a viable chance of becoming chief executive anytime soon."

Even before sub-prime credit hit the fan, women were finding it a tough slog into banking's upper ranks. According to Financial Women International, in 2005 just 18 percent of executive positions in the top 100 nationally chartered commercial banks were held by women.

Investment banks have implemented a number of programs over the years to aid women. For example, Citi and Deutsche Bank offer programs to help women understand that competence alone doesn't contribute to success, something men have known for a very long time.

But the departure of female leaders can have a more insidious affect on banking: Constance Helfat, professor of strategy at Dartmouth University's Tuck School of Business, observes that "women beget women," meaning that the more women occupy C-suites at a company, the greater chance other women will be promoted to the top. Thus, a company's gender culture is impacted by having executive-level females.