As President Bush prepares to disclose the details of his plan to funnel hundreds of billions of dollars of future Social Security funds into privately held investment accounts, Wall Street has begun a muted lobbying campaign, chastened by bolder forays that failed in years past.

So far, the chief executives of most financial firms have refused to take a public stand in support of private accounts, wary of being seen as too eager to embrace a potential new revenue stream.

At last week's White House economic meeting in Washington, they were conspicuous in their absence from the Social Security panel. Even in direct meetings with President Bush, who actively campaigned on the issue of Social Security, executives have shied away.

There are signs, however, that the industry is becoming a little more aggressive in pushing for private accounts, through a loose assemblage of trade associations, business coalitions and conservative research centers. These groups have lately begun trying to raise money from business interests and to marshal support on Capitol Hill, while also seeking to deflect criticism that Wall Street is behind the move simply to reap rich rewards for administering the accounts.

The first salvo was launched by the Securities Industry Association, which recently issued a research report arguing that the private accounts would not be a financial bonanza for Wall Street. In the paper, the association calculated that firms would collect at least $39 billion in fees, and perhaps considerably more, from managing such accounts over the next 75 years. But the group noted that the fees charged would be significantly below the fees that investment firms receive these days from low-cost mutual funds.

And even if the fees rose significantly as more people chose actively managed accounts, the association's report argued, they would still pale in comparison with the $3.3 trillion in revenues Wall Street firms are projected to earn from their core securities business over that period.

The Investment Company Institute, the lobbying arm for the mutual fund industry, has not endorsed private accounts nor has it lobbied Congress on the matter. But while its members are reluctant to speak out publicly on the topic, the institute recently hired as its communications director F. Gregory Ahern, a former executive at State Street Corporation in Boston who was involved in that firm's aggressive lobbying effort for private accounts during the late 1990's.

Behind the scenes, the Alliance for Worker Retirement Security, a business coalition advocating private accounts, has begun meeting with Congressional and White House staff members, pushing the idea that private accounts are not only good for the country but also good for business.

In November, Derrick A. Max, the alliance's executive director, met with Charles P. Blahous, a special assistant to the president who has been at the forefront in the White House on Social Security. They have a strong connection, because Mr. Blahous preceded Mr. Max at the alliance.

At the meeting were representatives from the Securities Industry Association, Charles Schwab & Company, and the United States Chamber of Commerce, all members of the alliance.

The Club for Growth, a group financed largely by conservative business leaders that supports like-minded Congressional candidates, has also been active in the drive for privately held Social Security accounts. Members include Richard Gilder of Gilder Gagnon Howe & Company, a private investment firm, and Charles H. Brunie, the founder of Oppenheimer Capital.

The club, which is run by Stephen Moore, who once served as economic adviser to the former House Republican Leader Dick Armey, recently sent out a memorandum to its backers proposing a $15 million public relations and grassroots campaign in favor of private accounts.

This increase in activity is occurring against the backdrop of a long-running campaign by the Cato Institute, a Washington policy research and lobbying organization with libertarian leanings that has received financial support from, among others, American Express and the American International Group, the large insurance company. State Street also provided funds in the past to support the institute's efforts to persuade Congress of the merits of personal accounts.

Opponents of personal accounts, led by labor unions and some state pension funds, accuse these groups of acting as a stalking horse for the financial industry.

"Our sense is there is a lot of activity behind the curtain," said Bill Patterson, the director of the office of investment at the A.F.L.-C.I.O. "There is a dangerous confluence between the industry and the ideologues of the right. These groups can't do it by themselves - they need the covert and overt support of the financial services industry."

Faced with such criticism, the financial industry has become particularly sensitive about how it approaches the issue of allowing individuals to invest some of their Social Security contributions in private accounts.

Unlike dividend and capital-gains tax cuts - White House policies that were loudly applauded by Wall Street - personal accounts are expected to come with strings attached, requiring an industry that has always been skeptical of intervention in the markets to work under the supervision of government- appointed trustees.

Many top Wall Street executives are strong supporters of President Bush and are philosophically in agreement with the idea of applying the independence of the capital markets to the Social Security program. They have raised millions of dollars in campaign contributions: Morgan Stanley and Merrill Lynch were among the top corporate supporters of the president's re-election campaign, raising over $1 million combined, according to the Center for Responsive Politics, a nonpartisan group that tracks political contributions and campaign spending.

Yet as executives of large and visible institutions, they are leery of becoming political whipping boys for opponents of the private accounts, and also are concerned that administering millions of small accounts may well be a money-losing proposition.

Indeed, when asked whether they support private accounts, officials from Morgan Stanley, Merrill Lynch, Vanguard and Fidelity all declined to discuss the issue.

Under the most widely discussed plans under consideration, personal accounts would be created by allowing workers to divert a portion of their payroll taxes into investment accounts set aside in their name. At first, individuals would be offered a limited range of investment vehicles, mostly low-cost indexed funds. After a time, account holders would be given the option to upgrade to actively managed funds, which would invest in a more diverse range of assets with higher risk and potentially larger fees.

Because Social Security taxes are used to pay benefits to current retirees, nearly all the plans envision the government borrowing as much as $2 trillion to fill the gap created by diversion of some payroll taxes. Proponents argue that the borrowing would pay for itself over the long run because the accounts, if they generated a higher return, would help reduce or eliminate the future obligations of the Social Security system.

Some specialists on Wall Street, however, are worried that adding to the budget deficit by such a large amount over the next couple of decades might put upward pressure on interest rates, a move that would not be helpful to the stock market. And with tens of millions of small accounts to handle, industry executives say they see little room for profit after administrative costs are subtracted.

Whatever the ultimate benefit, Wall Street's top executives worry that any visible lobbying campaign on their part could well do more harm than good for President Bush's cause.

"There has been no lobbying because the industry knows it will be accused of making windfall profits," said Robert C. Pozen, the chairman of MFS Investment Management and a member of the White House-sponsored commission in 2001, led by the New York Senator Daniel P. Moynihan and Richard Parsons, chief executive of Time Warner, that developed several alternative plans for establishing private Social Security accounts.

Despite that accusation, Mr. Pozen argued, the program will not be the windfall its critics claim.

"The accounts are so small," he said, "that the vast majority of firms would not want to touch them. It's just not a bonanza for the industry." There are already signs that political opponents are lining up to tar the White House proposal by linking it to Wall Street greed. Last week, John J. Sweeney, the A.F.L.-C.I.O. president, sent a letter to 46 financial companies, including Morgan Stanley, Merrill Lynch and Fidelity, asking them to publicly disavow the creation of personal accounts.

In the letter, Mr. Sweeney cited the example of State Street, which in 2002, under pressure from the A.F.L.-C.I.O., reversed a position it long held that private accounts were the best means to address the long-run financing squeeze on Social Security. The firm changed its position after its former chief executive, Marshall Carter, retired. Mr. Carter had set himself apart from his peers by advocating the accounts through speeches and by co-writing a book supporting them with William G. Shipman, another former State Street executive.

State Street's experience and the unsuccessful effort in 2002 by an industry group, the Coalition for American Financial Security, are among the main reasons Wall Street has been so reluctant to assume a bolder approach in pushing for the accounts.

"I think the backlash occurred at two levels," said Sylvester Scheiber of Watson Wyatt, a corporate benefits and financial consulting firm that was a member of the coalition. "There was pressure from clients and the press has been negative toward them. These folks are very image conscious and they don't want to be branded as 'make a buck at any price.' "

Still, while refraining from pushing the issue directly, firms like Merrill Lynch have taken a more oblique tack. For years now, Merrill Lynch has run ads about the virtues of retirement saving (with no mention of private accounts) in the back pages of Roll Call, a small newspaper that closely follows Congressional activities and is read avidly by members of Congress.

In keeping with their low profile, Wall Street executives have been wary about discussing the issue even in private. Last month, at a meeting with President Bush at the White House, Philip J. Purcell, Morgan Stanley's chief executive, and his counterparts, E. Stanley O'Neal of Merrill Lynch and Henry M. Paulson Jr. of Goldman Sachs, were among a group that discussed the state of the economy and the markets.

But none of the participants, according to a person who was briefed on the session, opened the topic of private Social Security accounts.