What looked to be a failed plan to rescue Lehman Brothers may be triggering a stunning transformation of the Wall Street landscape today as two of the biggest names in finance, Bank of America and Merrill Lynch, were talking about combining.

A forced restructuring of the world’s largest insurance company, American International Group Inc., also weighed heavily on global markets as the ripple effects of the year-old credit crisis seemed to intensify.

A global consortium of banks, working with government officials in New York, was racing to create a pool of funds worth up to $100 billion to lend to troubled financial companies. The aim, according to participants who spoke to The Associated Press, was to prevent a worldwide panic on stock and other financial exchanges.

Futures pegged to the Dow Jones industrial average fell almost 300 points in electronic trading this evening, pointing to a sharply lower open for the blue chip index tomorrow morning. The first markets open in Asia — in Australia, New Zealand, and Taiwan — were also falling.

Lehman Brothers may be forced to seek an orderly unwinding of its businesses. All potential buyers walked away after the U.S. Treasury refused to budge on its refusal to provide any takeover aid, as it had done six months ago when Bear Stearns faltered.

Expectations that the 158-year-old Lehman would survive dimmed after Barclays PLC withdrew its bid to buy the investment bank. Barclays and Bank of America were considered front-runners to buy Lehman, which is foundering under the weight of $60 billion in soured real estate holdings.

The New York Insurance Superintendent, Eric Dinallo, and a representative of the governor’s office spent the weekend at the headquarters of insurer AIG, hit hard by deterioration in the credit markets, trying to craft a solution that protects policyholders, according to Dinallo’s spokesman David Neustadt.

Merrill Lynch, another investment bank laid low by the crisis that was triggered by rising mortgage defaults and plunging home values in America, was in talks to be acquired by Bank of America, a marriage apparently brokered by the federal government.

Charlotte, N.C.-based Bank of America has the most deposits of any American bank, while Merrill Lynch is the world’s largest brokerage. A combination of the two would create a global financial giant to rival Citigroup Inc., the biggest American bank in terms of assets.

The deal would not come without risks, however. Merrill Lynch, like many of its Wall Street peers, has been struggling with tight credit markets and billions of dollars in assets tied to mortgages that have plunged in value. Merrill has reported four straight quarterly losses.

And Bank of America’s own finances are far from robust. As consumer credit deteriorates, the bank has seen its profits decline, and the company is still in the midst of absorbing the embattled mortgage lender Countrywide Financial, which it acquired in January.

The stunning weekend developments took place as voters, who rank the economy as their top concern, prepare to elect a new president in seven weeks.

The weekend’s developments will likely spur a much greater focus by presidential candidates — Senators McCain and Obama — and members of Congress on the need for stricter financial regulation.

A finance professor emeritus at Harvard Business School, Samuel Hayes, said the current administration may get a lot of blame for the situation, which could benefit Mr. Obama.

“Just the psychological impact of this kind of failure is going to be significant,” he said. “It will color people’s feelings about their well-being and the integrity of the financial system.”

Mr. Paulson was huddled through the weekend at the New York Federal Reserve’s fortress-like building in downtown Manhattan with executives from major banks and investment houses to hash out the fate of Lehman Brothers and to staunch the bleeding on Wall Street that threatened to shatter investor confidence around the globe.

“It’s clear we’re one step away from a financial meltdown,” chairman of the consulting firm RGE Monitor, Nouriel Roubini, said.

Nudged by the Treasury Department and the Fed, American and foreign banks appeared ready to cooperate on a plan to shore up the global financial system. According to an investment banking official, they would create as much as a $100 billion pot to help out troubled investment firms and banks.

The Fed was ready to chip in, too, with more largesse in its emergency lending program for commercial and investment banks. The official, who had direct knowledge of the talks at the New York Fed, asked not to be named because the discussions over the plan were ongoing.

The meetings that began Friday night were a who’s who of financial heavyweights: Mr. Paulson, the president of the New York Fed, Timothy Geithner, the Securities and Exchange Commission Chairman, Christopher Cox, and a host of CEOs, including Vikram Pandit of Citigroup Inc., Jamie Dimon of JPMorgan Chase & Co., John Mack of Morgan Stanley, Lloyd Blankfein of Goldman Sachs Group Inc., and Merrill Lynch & Co.’s John Thain.

For all their efforts, Lehman appeared ready to file for bankruptcy.

The end of Lehman may not stop the financial crisis that has gripped Wall Street for months, analysts said. More investment banks could disappear soon.

The independent broker-dealers “are going the way of the dodo bird,” an Alexandria, Va.-based banking consultant, Bert Ely, said.

That’s partly because some of the firms, particularly Merrill, made bad bets on real estate. But several analysts said that investment companies will need the deep pockets of commercial banks to survive the next few years.

Mr. Roubini said with no deal for Lehman, Merrill and the other investment firms would have been hit with a “run on the bank,” as hedge funds and other clients withdraw funds and banks become reluctant to lend to them. Many of the investment banks rely on short-term loans to finance their day-to-day operations.

The cost of insuring financial firms’ debt from default has been soaring.

A rise in the cost of the insurance, known as credit default swaps, indicates debt holders believe there is a greater chance of default by the financial companies. Especially over the past week, those insurance costs have been increasing rapidly as more debt holders fear companies like Lehman Brothers and Washington Mutual Inc. could collapse and not be able to repay their debt.

Swaps on most financial firms are likely to get even worse during the upcoming week, analysts said.

Today, there was also an emergency trading session being held at the International Swaps and Derivatives Association to “reduce risk associated with a potential Lehman Brothers Holdings Inc. bankruptcy.” The ISDA, which arranges trades for derivatives, said it was allowing customers to make trades and unwind positions linked to Lehman — but that those trades would be

Mr. Roubini said it’s difficult to accurately gauge the health of companies like Merrill because their financial health depends on how they value complex securities. As a result, their finances aren’t very transparent, he said.

That can lead to a loss of confidence in the financial markets, he said, which can overwhelm an investment bank even if it is financially healthy by some measures.

“Once you lose confidence, the fundamentals matter less,” he said.

Mr. Ely said similar shake-outs have happened in other parts of the financial industry, such as credit cards and thrifts. Bank of America acquired independent credit card issuer MBNA in 2005, for example, while credit card company Capital One Financial Corp. has diversified itself by purchasing regional banks in Louisiana, Texas, and New York.

The common denominator of the financial crisis, analysts said, is the bursting of the housing bubble. Home prices have dropped on average 25% so far. Mr. Roubini predicted they could drop another 15%.

The crisis has begun to slow the broader economy as banks make fewer loans and consumers have begun cutting spending. Many economists are now forecasting that the economy could slip into recession by the end of this year and early next year.

That, in turn, could cause additional losses for commercial banks on credit cards, auto loans, and student loans.

The Fed is widely expected to keep interest rates steady at 2%, below inflation, when it meets Tuesday. It was possible, however, that the central bank might decide in coming weeks to cut rates if such a move is seen as needed to calm turbulent financial markets.

The International Monetary Fund predicted earlier this year that total losses from the credit crisis could reach almost $1 trillion. So far, banks have only taken about $350 billion in losses.

Commercial banks are also starting to feel the pinch. Eleven have closed so far this year, including Pasadena, Calif.-based IndyMac Bank, which had $32 billion in assets and $19 billion in deposits.

The managing director of Institutional Risk Analytics, Christopher Whalen, a research firm, predicts that approximately 110 banks with $850 billion in assets could close by next July. That’s out of 8,400 federally insured institutions, he said, which together hold $13 trillion in assets.

Individual customers are starting to get nervous about the financial health of their banks for the first time in generations, he said. Mr. Whalen’s firm analyzes the safety and soundness of banks for business clients, but began receiving inquiries from individuals in the past two months for the first time, he said.

“If we don’t get ahead of this, we are going to face a run on the retail banks by election day,” he said.