Kenneth Langone, co-founder of Home Depot and former director of the New York Stock Exchange, faces an increasingly uphill fight to mount even a semblance of a challenge to the merger of the stock exchange and Archipelago. His main problem is money.

Despite being a billionaire, Mr. Langone has failed to win the support he sought from Wall Street’s leading investment banks, and so lacks the resources to challenge the Big Board’s $3.3 billion bid. To scuttle the deal, according to the merger agreement announced last week, would require Mr. Langone to raise $3 billion. So far, it appears he has only $200 million committed to the effort.

Mr. Langone is no stranger to the stock exchange, having served for four years as one of its directors during the tenure of Richard Grasso as the Big Board’s chief executive officer.

Mr. Langone’s role in crafting Mr. Grasso’s $187.5 million severance package led to his being sued by the office of the New York State attorney general, Eliot Spitzer. Mr. Spitzer alleges Mr. Langone misled fellow board members about the amount of Mr. Grasso’s compensation. Mr. Langone has vigorously maintained his innocence, with his spokesman, Jim McCarthy, telling The New York Sun yesterday, “Every bit of info that has come out validates Mr. Langone’s claims. He is innocent and Mr. Spitzer’s case is going south.” The lawsuit seeks $12 million in damages from Mr. Langone.

Mr. Langone announced Monday that he was working with the former chief executive officer of Credit Suisse First Boston, John Mack, and Duquesne Capital Management’s founder and general partner, Stanley Druckenmiller, to study the valuation of the Big Board’s merger.

Mr. Druckenmiller, who became famous managing George Soros’s Quantum Fund in the 1990s, when it regularly posted yearly returns of 30% or more, matched Mr. Langone’s $100 million with $100 million of his own.

Mr. Mack, whose influence is still considerable on Wall Street despite his departure from Credit Suisse last June, is to oversee a study examining the valuation placed on the stock exchange’s 1,366 seats in the deal. Each seat represents an ownership interest in the stock exchange that confers floor brokerage and trading rights to the holder. Mr. Langone’s spokesman declined to identify who is performing the study or when it will be completed.

Including $300,000 in cash for each holder, the deal between the exchange and Archipelago that was announced last week would value each seat at $2.6 million, an increase of almost 33% from the $1.8 million at which a seat traded the week before the merger agreement.

Mr. Langone has said, however, that the stock exchange’s 1,366 seat-holders are being shortchanged in the Archipelago merger, arguing that they deserve more than the proposed 70% of the new company, which is to be called NYSE Group. He did not place a value on the seats. A spokesman for the stock exchange did not return a call.

It appears that if Mr. Mack and Mr. Langone do anything, it will be without some of the major investment banks, at least to start.

A meeting Tuesday among Mr. Mack and senior executives at Merrill Lynch, J.P. Morgan Securities, Bank of America, Wachovia, Bear Stearns, and Lehman Brothers ended with the dealers refusing to pony up as little as $100,000 each to hire a lawyer and an investment bank to do the valuation. The group, according to the New York Times, agreed only to “stay in touch.”

Among those who doubt that Mr. Langone will be able to convince the stock exchange’s seat-holders is the principal of the Aite Group, a Boston based financial research and regulatory consulting firm, Sang Lee.

“Let’s assume he gets more than $3 billion,” Mr. Lee said. “Where is his plan? How will he introduce the electronic-trading capabilities and movement into other markets that John Thain has proposed? Because without them, the NYSE is pretty much done.” Mr. Thain is the former Goldman Sachs executive who heads the stock exchange and announced the pact with Archipelago.

Another consideration is Mr. Langone’s court fight with Mr. Spitzer, Mr. Lee said.

“Who looks at this guy and sees a proposal for an NYSE that is in better shape than two weeks ago?” the Aite principal said of Mr. Langone.

The attitude toward Mr. Langone’s bid among the stock exchange’s 425 specialists – the floor traders charged with maintaining orderly markets in stocks – is one of skepticism, according to the president of the Specialist Association, David Humphreville.

“We haven’t really seen the concrete economic proposals from him,” Mr. Humphreville said. “It seems a lot more personal, like he’s trying to derail some thing that has pretty broad support down here.”

Mr. Humphreville did say that specialists and floor traders would listen to a “realistic offer, backed by a serious plan,” from Mr. Langone if one emerged.

An individual within Mr. Langone’s group – who spoke on condition of anonymity, given regulatory considerations – disagreed with the assertion that the effort was in hot water. The source said the meeting with the investment banks “got firms to commit to examine the independent valuation once we’re done.”

The source also said Mr. Langone had persuaded a former Merrill Lynch CEO, Daniel Tully, to join his group, and that Mr. Tully had indicated he would be financially supporting any offer Mr. Langone made. The source declined to say how much Mr. Tully offered to contribute. Mr. Tully could not be reached, and a spokesman for Merrill Lynch did not return a call.

The individual within Mr. Langone’s group said one point of agreement among the investment banks and Messrs. Mack, Langone, and Tully was displeasure over Goldman Sachs’s role in representing both Archipelago and the stock exchange in the transaction. That is a rare occurrence in the lucrative world of mergers-and-acquisition advising, in which buyer and seller generally each have their own adviser. In an interview with wire services Monday, Mr. Langone termed Goldman’s dual roles “unseemly.”

Documents released yesterday shed light on the deal’s value to Goldman. Archipelago agreed to pay Goldman $3.5 million for advising on the transaction, according to a filing with the Securities and Exchange Commission. The disclosure also said Goldman owns about 21 seats on the stock exchange, worth about $2.6 million each, and owns 15.5% of Chicago-based Archipelago,a position that has increased in value by about $82 million since the transaction was announced last week. Should the deal be approved, Goldman would own 5.7% of NYSE Group.

A Goldman spokesman, Lucas van Praag, as quoted by Bloomberg News, rejected suggestions that the firm had any conflicts of interest. The NYSE-Archipelago transaction has had “total transparency,” he said.