The executives are a study in contrasts. One is a brash risk-taker who bootstrapped his way from an Alabama cotton farm to one of Wall Street's largest brokerage firms. The other made his mark as a consensus-builder who leveraged ties to one of America's most powerful families to eventually lead the world's largest media company.

E. Stanley O'Neal, 56, at Merrill Lynch and Richard D. Parsons, 59, at Time Warner, have nevertheless inhabited the public imagination as two executives who helped rewrite history by breaking down cultural barriers and rising to lead Fortune 500 companies.

But O'Neal retired under pressure this week after an $8.4 billion write-down in the quarter, a loss of $2.3 billion and an unauthorized merger approach to a rival bank. And Parsons has announced that he plans to retire by March at the latest. He has been under pressure to turn the reins over to the president of Time Warner, Jeffrey L. Bewkes, whom analysts say is more likely to accelerate a shakeup by spinning off business units like AOL and Time Warner Cable.

Along with ruminations on their legacies, their situations have triggered a debate over whether their accomplishments have helped break down barriers facing a younger generation of black executives angling for the corner office.

Losing ground in leadership spots

Industry observers and civil rights leaders say O'Neal's ouster has shed much-needed light on the dearth of blacks in so-called C-level positions in corporations, while underscoring the extent to which executive suites and boardrooms remain bastions of white male dominance.

The subject of race has proven to be delicate for black executives, many of whom prefer to view themselves as — at least publicly — "an executive who happens to be black." They have earned the right through hard work, they say, to be judged on their merits.

"We have demonstrated that we can not only run companies and in many cases, run them quite well," said Marc Morial, president of the National Urban League, a nonprofit civil rights organization. "There is an abundance of African American talent out there. My hope is that they will get their chance to rise up and pick up the mantle."

The chief executive of StarCom, Renatta McCann, said, "The victories of leaders like Stanley O'Neal and Richard Parsons are both symbolic and transformational."

"That said, we have yet to reach a tipping point where the pipeline organically regenerates," McCann said. "We have to achieve momentum and velocity and it has to achieve scale to make it sustainable."

Although some bloggers this week raised questions of race in O'Neal's ouster, analysts and those with knowledge of Merrill's actions, say that was not the case.

O'Neal was judged, they said, by the same standards of others in his position: The company's performance and his relationship to the board.

O'Neal could not be reached for comment.

A spokesman for Merrill, Jason H. Wright, said: "During the years Stan was here, as an organization we very much embraced a meritocracy and inclusiveness that has translated into a more diverse work force that we're proud of. The board has been very engaged in those initiatives and has no intention of changing, regardless of who is CEO."

Beyond such visible exceptions as O'Neal and Parsons, some corporate diversity specialists say that in recent years, blacks have gradually lost ground in leadership pipelines to other minorities.

"When Carleton Fiorina left Hewlett-Packard, people said it was a rough time for women in the executive suite, but women in corporate America seem to be doing a lot better these days than African Americans," said Frank Dobbin, a professor of sociology at Harvard University who studies corporate diversity issues. "Forty years after the Civil Rights Acts were passed, we're much further behind than we should be."

Martin Davidson, a professor at the Darden Graduate School of Business at the University of Virginia, put it another way: "An individual can rise to the top for many reasons, and their rise does not mean that a real shift in the system has occurred. It could be many years before we see another African-American CEO of a major corporation."

Diversity efforts high, execs low

Aylwin B. Lewis, CEO and president of Sears Holdings Corp., said: "We are building a culture where every associate has an opportunity to excel, if they're willing to put in the work. We judge people by what they accomplish, not by who they are, what they believe or where they came from."

According to Management Leadership for Tomorrow, a nonprofit corporate diversity consulting firm, the pipeline for black executives has accounted for less than 5 percent of top entry-level positions, and less than 3 percent of senior management jobs last year.

Though 15 percent of college graduates are black or Hispanic, they only represent 8 percent of MBA students at the top 25 business schools, only 3 percent of senior management positions and 1.6 percent of Fortune 1000 chief executives, said John Rice, president of MLT.

The irony, Rice said, is that companies have become more aggressive in their diversity efforts. Among the catalysts have been settlement payments in racial bias lawsuits. In 1997, for instance, Texaco settled a class-action lawsuit for $176 million. In 2000, about 2,000 employees won a $192.5 million settlement from Coca-Cola.

"Still, the number of blacks in those stepping-stone positions is very small," Rice said. "The reason there is no critical mass is that most companies focus only on short-term outcomes."

Some black executives preside over several large companies

Kenneth I. Chenault American Express

Ronald A. Williams Aetna

Clarence Otis Jr. Darden Restaurants

Aylwin B. Lewis Sears

John W. Thompson Symantec

Several blacks also run or hold senior roles in major subsidiaries of Fortune 500 companies:

Lloyd G. Trotter, president and CEO of General Electric Industrial Systems

Don Thompson, president of McDonald's USA

James A. Bell, CFO and executive vice president of finance of the Boeing Co.

Ursula Burns, president of Xerox

— New York Times