A year after the crisis struck, many of the industry’s behemoths  those institutions deemed too big to fail  are, in fact, getting bigger, not smaller. For many of them, it is business as usual. Over the last decade the financial sector was the fastest-growing part of the economy, with two-thirds of growth in gross domestic product attributable to incomes of workers in finance.

Now, the industry has new tools at its disposal, courtesy of the government.

With interest rates so low, banks can borrow money cheaply and put those funds to work in lucrative ways, whether using the money to make loans to companies at higher rates, or to speculate in the markets. Fixed-income trading  an area that includes bonds and currencies  has been particularly profitable.

“Robust trading results led the way,” said Howard Chen, a banking analyst at Credit Suisse, describing the latest profits.

To prevent a catastrophic financial collapse that would have sent shock waves through the economy, the government injected billions of dollars into banks. Some large institutions, like Goldman and Morgan, have since repaid their bailout money. But most of the industry still enjoys other forms of government support, which is helping to stoke profits.

Goldman Sachs and its perennial rival Morgan Stanley were allowed to transform themselves into old-fashioned bank holding companies. That switch gave them access to cheap funding from the Federal Reserve, which had been unavailable to them.

Those two banks and others like JPMorgan were also allowed to issue tens of billions of dollars of bonds that are guaranteed by the Federal Deposit Insurance Corporation, which insures bank deposits. With the F.D.I.C. standing behind them, the banks could borrow the money on highly advantageous terms. While some have since issued bonds on their own, they nonetheless enjoy the benefits of their cheap financing.

Granted, banks are also benefiting from a stabilizing economy. The fear that gripped the markets earlier this year, when doomsayers predicted a second Great Depression, has largely dissipated. Stocks, corporate bonds, even risky corporate i.o.u.’s  have all rallied from their bear market lows, some spectacularly so. The Dow Jones industrial average has soared 50 percent this year, and touched 10,000 this week for the first time since the crisis.