NEW YORK - Citigroup and Bank of America were the reigning champions of finance in 2006 as home prices peaked, leading the 10 biggest U.S. banks and brokerage firms to their best year ever with $104 billion of profits.

By 2008, the housing market's collapse forced those 10 biggest banks and brokerages to take more than six times as much, $669 billion, in emergency loans from the Federal Reserve. The loans dwarfed the $160 billion in public bailouts the top 10 got from the U.S. Treasury, yet until now the full amounts have remained secret.

Fed Chairman Ben Bernanke's unprecedented effort to keep the economy from plunging into depression included lending banks and other companies as much as $1.2 trillion of public money, about the same amount U.S. homeowners currently owe on 6.5 million delinquent and foreclosed mortgages. The largest borrower, Morgan Stanley, got as much as $107.3 billion, while Citigroup took $99.5 billion and Bank of America $91.4 billion, according to a Bloomberg News compilation of data obtained through Freedom of Information Act requests, months of litigation and an act of Congress.

"These are all whopping numbers," said Robert Litan, a former Justice Department official who in the 1990s served on a commission probing the causes of the savings-and-loan crisis. "You're talking about the aristocracy of American finance going down the tubes without the federal money."

It wasn't just American finance. Almost half of the Fed's top 30 borrowers, measured by peak balances, were European firms. They included Edinburgh-based Royal Bank of Scotland, which took $84.5 billion, the most of any non-U.S. lender, and Zurich-based UBS, which got $77.2 billion. Germany's Hypo Real Estate Holding borrowed $28.7 billion, an average of $21 million for each of its 1,366 employees.

The largest borrowers also included Dexia, Belgium's biggest bank by assets, and Societe Generale, based in Paris, whose bond-insurance prices have surged in the past month as investors speculated that the spreading sovereign debt crisis in Europe might increase their chances of default.

The $1.2 trillion peak on Dec. 5, 2008 - the combined outstanding balance under the seven programs tallied by Bloomberg - was almost three times the size of the U.S. federal budget deficit that year and more than the total earnings of all federally insured banks in the U.S. for the decade through 2010, according to data compiled by Bloomberg.

The balance was more than 25 times the Fed's pre-crisis lending peak of $46 billion on Sept. 12, 2001, the day after terrorists attacked the World Trade Center in New York and the Pentagon.

The Fed has said it had "no credit losses" on any of the emergency programs, and a report by Federal Reserve Bank of New York staffers in February said the central bank netted $13 billion in interest and fee income from the programs from August 2007 through December 2009.

"We designed our broad-based emergency programs to both effectively stem the crisis and minimize the financial risks to the U.S. taxpayer," said James Clouse, deputy director of the Fed's division of monetary affairs in Washington. "Nearly all of our emergency-lending programs have been closed. We have incurred no losses and expect no losses."

While the 18-month U.S. recession that ended in June 2009 after a 5.1 percent contraction in gross domestic product was nowhere near the four-year, 27 percent decline between August 1929 and March 1933, banks and the economy remain stressed.

The odds of another recession have climbed during the past six months, according to five of nine economists on the Business Cycle Dating Committee of the National Bureau of Economic Research, an academic panel that dates recessions.

Bank of America's bond-insurance prices last week surged to a rate of $342,040 a year for coverage on $10 million of debt, above where Lehman Brothers Holdings' bond insurance was priced at the start of the week before the firm collapsed. Citigroup's shares are trading below the split-adjusted price of $28 that they hit on the day the bank's Fed loans peaked in January 2009. The U.S. unemployment rate was at 9.1 percent in July, compared with 4.7 percent in November 2007, before the recession began.

Homeowners are more than 30 days past due on their mortgage payments on 4.38 million properties in the United States, and 2.16 million more properties are in foreclosure, representing a combined $1.27 trillion of unpaid principal, estimates Jacksonville, Fla.-based Lender Processing Services Inc.

"Why in hell does the Federal Reserve seem to be able to find the way to help these entities that are gigantic?" Rep. Walter Jones, R-N.C., said at a June 1 congressional hearing in Washington on Fed lending disclosure. "They get help when the average businessperson down in eastern North Carolina, and probably across America, they can't even go to a bank they've been banking with for 15 or 20 years and get a loan."

The sheer size of the Fed loans bolsters the case for minimum liquidity requirements that global regulators last year agreed to impose on banks for the first time, said Litan, now a vice president at the Kauffman Foundation, which supports entrepreneurship research. Liquidity refers to the daily funds a bank needs to operate, including cash to cover depositor withdrawals.

The rules, which mandate that banks keep enough cash and easily liquidated assets on hand to survive a 30-day crisis, don't take effect until 2015. Another proposed requirement for lenders to keep "stable funding" for a one-year horizon was postponed until at least 2018 after banks showed they'd have to raise as much as $6 trillion in new long-term debt to comply.

Regulators are "not going to go far enough to prevent this from happening again," said Kenneth Rogoff, a former chief economist at the International Monetary Fund and now an economics professor at Harvard.

Reforms undertaken since the crisis might not insulate U.S. markets and financial institutions from the sovereign budget and debt crises facing Greece, Ireland and Portugal, according to the U.S. Financial Stability Oversight Council, a 10-member body created by the Dodd-Frank Act and led by Treasury Secretary Timothy Geithner.

"The recent financial crisis provides a stark illustration of how quickly confidence can erode and financial contagion can spread," the council said in its July 26 report.

Any new rescues by the U.S. central bank would be governed by transparency laws adopted in 2010 that require the Fed to disclose borrowers after two years.

Fed officials argued for more than two years, saying that releasing the identities of borrowers and the terms of their loans would stigmatize banks, damaging stock prices or leading to depositor runs. A group of the biggest commercial banks last year asked the Supreme Court to keep at least some Fed borrowings secret. In March, the high court declined to hear that appeal, and the central bank made an unprecedented release of records.

Data gleaned from 29,346 pages of documents obtained under the Freedom of Information Act and from other Fed databases of more than 21,000 transactions make clear for the first time how deeply the world's largest banks depended on the central bank to stave off cash shortfalls. Even as the firms asserted in news releases or earnings calls that they had ample cash, they drew Fed funding in secret, avoiding the stigma of weakness.

Two weeks after Lehman's bankruptcy in September 2008, Morgan Stanley countered concerns that it might be next to go by announcing it had "strong capital and liquidity positions." The statement, in a Sept. 29, 2008, news release about a $9 billion investment from Tokyo-based Mitsubishi UFJ Financial Group, said nothing about Morgan Stanley's Fed loans.

That was the same day as the firm's $107.3 billion peak in borrowing from the central bank, which was the source of almost all of Morgan Stanley's available cash, according to the lending data and documents released more than two years later by the Financial Crisis Inquiry Commission. The amount was almost three times the company's total profits over the past decade, data compiled by Bloomberg show.

Mark Lake, a spokesman for New York-based Morgan Stanley, said the crisis caused the industry to "fundamentally re-evaluate" the way it manages its cash.

"We have taken the lessons we learned from that period and applied them to our liquidity-management program to protect both our franchise and our clients going forward," Lake said. He declined to say what changes the bank had made.

In most cases, the Fed demanded collateral for its loans - Treasuries or corporate bonds and mortgage bonds that could be seized and sold if the money wasn't repaid. That meant the central bank's main risk was that collateral pledged by banks that collapsed would be worth less than the amount borrowed.

As the crisis deepened, the Fed relaxed its standards for acceptable collateral. Typically, it accepts only bonds with the highest credit grades, such as U.S. Treasuries. By late 2008, it was accepting "junk" bonds, those rated below investment grade. It even took stocks, which are first to get wiped out in a liquidation.

"What you're looking at is a willingness to lend against just about anything," said Robert Eisenbeis, a former research director at the Federal Reserve Bank of Atlanta.