The wrenching reshaping of Wall Street -- which over the weekend included the demise of one big firm and the sale of another -- also pushed the value of the dollar lower. It sent the price of crude oil below $100 a barrel for the first time since Feb. 15 as traders bet a global downturn would reduce the demand for energy. Wall Street's biggest shakeout since the Great Depression stems from a collapse in housing prices, which spread losses among firms that bet on securities linked to mortgages. Twice in the past year, regulators intervened to save financial firms and prevent further erosion in the housing markets. But over the weekend, officials drew the line at rescuing the storied investment bank Lehman Brothers, which Monday filed for bankruptcy protection. 'We had a very, very tough day on the market,' said Art Hogan, chief market analyst at Jefferies & Co. 'Investors are anxious about the spillover effect of Lehman and what is the next shoe to drop.' One huge concern is that the Lehman bankruptcy will probably trigger even tighter credit -- making it more difficult for everyone from large companies to small businesses to American home buyers to borrow money. There were also worries that Lehman's problems would infect other financial companies and spread to global stock markets, further harming the U.S. and global economies. The Fed meets today to decide interest rate policy. It's widely expected to keep rates at 2 percent, but some economists believe it could lower them to soothe Wall Street's frazzled nerves. The financial turbulence could also further derail consumer confidence in the economy just as stores prepare for the critical holiday shopping season. The upheaval in the financial system also means that consumers with marginal credit histories will have an even harder time getting loans, cutting into consumer spending. 'The backdrop even without this was tough. This certainly adds to the worry level,' said Michael P. Niemira, chief economist at The International Council of Shopping Centers. In the meantime, Treasury Secretary Henry M. Paulson Jr. signaled Monday that taxpayer funds could still be used broadly to 'maintain the stability and orderliness of our financial system' but that he was pressing healthier Wall Street firms and commercial banks to join together to assist in rescuing individual firms -- much like the purchase of Merrill Lynch on Sunday by Bank of America. Goldman Sachs, for instance, was asked by the Federal Reserve Bank of New York to help AIG, a $1 trillion-asset insurance company that serves 74 million consumers in 130 countries. AIG had been heavily involved in the business of issuing complex insurance contracts to investors in securities backed by mortgages, and the collapse of subprime and other home loans threatened to hobble the company and trigger a chain reaction in the financial system. J.P. Morgan Chase, which is serving as AIG's financial adviser, was seeking support for a credit line of $70 billion to $75 billion that would involve multiple lenders, spreading the risk, according to two sources familiar with the discussions. They spoke on condition of anonymity because the talks were private. New York's governor, meanwhile, said his state would allow AIG to use $20 billion from its own insurance subsidiaries to ease a financial crunch. By posting the assets as collateral, AIG can borrow money to run its day-to-day operations, Gov. David A. Paterson said. The move required special dispensation from state insurance superintendent Eric R. Dinallo, who is responsible for protecting the stability of AIG insurance companies in New York and their policyholders. 'It's no secret that the company has been talking to the Feds and talking to us,' Paterson said. 'They asked us what assistance we could provide, and this is our idea.' A deal to rescue AIG may have to come quickly now that Standard & Poor's and Moody's Investors Service have lowered their credit ratings for the firm, should the decision force AIG to boost its collateral to meet its obligations. The Fed has maintained that it will not offer AIG a bridge loan or other direct injection from the government, according to sources familiar with the conversations. AIG executives huddled at their Manhattan headquarters over the weekend with potential private investors. 'I don't think anybody is going to lend that amount of money at terms that are anywhere near economically feasible without a backstop, without some form of guarantee, say by the Fed or another party,' said Donn Vickrey of Gradient Analytics, who has been warning of trouble at AIG for months. At the same time, the Fed over the weekend made it easier for investment banking firms to borrow money by agreeing to accept a wider range of assets as collateral, including mortgage-backed securities that banks may not be able to sell. The Associated Press contributed to this report.