NEW YORK -- Wall Street snapped back Tuesday after its biggest sell-off in years amid growing expectations that lawmakers will salvage a $700 billion rescue plan for the financial sector. But the seized-up credit markets where businesses turn to raise money showed no sign of relief.

One day after the biggest point drop in its history, the Dow Jones industrial average rose 485 points, or more than 4.5 percent -- the latest in a string of extraordinarily volatile days in the stock market. It was third-biggest point gain in the Dow's history and the biggest percentage climb in the Dow in six years.

A board over the trading floor shows the Dow Jones industrial average jumping 485.21 points, or 4.68 percent, to 10,850.66 after the closing bell at the New York Stock Exchange September 30, 2008. Wall Street roared back on Tuesday, a day after its worst sell-off in 21 years, as investors bet Washington would revive a plan to stabilize the U.S. financial sector after Monday's surprise defeat on Capitol Hill. [Agencies]

The recovery in stocks wasn't unexpected as carnage on Wall Street often attracts bargain hunters, though questions remain about how investors will proceed. Without a bailout plan in place to absorb soured mortgage debt and other bad loans from battered banks, investors are left wondering what might restore confidence in lending.

Major stock indexes were almost a sideshow during the session, with the credit markets as the main event. A key rate that banks charge to lend to one another shot higher, a tightening of the availability of credit that could cascade through the economy.

Traders on the floor of the New York Stock Exchange, still stunned from Monday's 778-point rout in the Dow, warned that the government needs to approve a plan that will sweep away the fears that hobbled the credit markets. While US political leaders have vowed to revisit the issue, the House isn't slated to meet again until Thursday.

"If it doesn't pass, then look out below," said Jason Weisberg, an NYSE trader for Seaport Securities. "It could get ugly."

Though the blue-chip index rose sharply Tuesday, the main worry for traders is that a lack of a plan will make it nearly impossible for some companies to fund basic operations like making payroll. Participants in the credit market buy and sell debt that companies use to finance operations.

The benchmark London Interbank Offered Rate, or LIBOR, that banks charge to lend to one another, rose sharply Tuesday, making it more expensive and difficult for consumers and businesses to borrow money. In addition, credit card debt and more than half of adjustable-rate mortgages are tied to LIBOR, so an increase isn't welcome for many consumers.

LIBOR for 3-month dollar loans rose to 4.05 percent from 3.88 percent on Monday. LIBOR for 3-month euro loans, meanwhile, rose to 5.27 percent, from 5.22 percent Monday.