Stocks staged a partial rebound early today after their biggest sell-off in years, though financial markets remained troubled a day after lawmakers rejected a $700 billion rescue plan for the financial sector.A key rate that banks charge to lend to one another shot higher, a tightening of the availability of credit that could spill through the economy.A snapback 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 banks’ balance sheets, investors are wondering what might be able to restore confidence in lending.While stocks turned higher, moves in the credit markets were more ominous. The benchmark London Interbank Offered Rate, or LIBOR, that banks charge to lend to one another rose today, making it more expensive and difficult for consumers and businesses to borrow money. In addition, more than half of adjustable-rate mortgages are tied to LIBOR, so an increase isn’t welcome for many homeowners.LIBOR for 3-month dollar loans rose to 4.05 percent from 3.88 percent on Monday. LIBOR for 3-month euro loans, meanwhile, jumped to 5.27 percent, from 5.22 percent Monday.Many on Wall Street had expected the plan would help sweep away some of the fear and pessimism that has hobbled credit markets, which are where businesses turn to finance their day-to-day operations. Some critics have said, however, the plan was too costly and wouldn’t have done enough to jump-start lending.While U.S. political leaders have vowed to revisit the issue, the House isn’t slated to meet again until Thursday. President Bush said in a statement from the White House early today the damage to the economy will be “painful and lasting” unless Congress passes the bailout measure.Many traders likely will proceed cautiously while they gauge prospects for resurrecting the government’s bailout effort, which was backed by leaders of both parties.And today brings the final session of the third quarter — and what is typically the worst month for the stock market — so some portfolio managers might try to do what they can to dress up their performance or could simply wish to dump holdings in an unpopular corners of the market like the financials.In the first half-hour of trading, the Dow Jones industrial average rose 190.51, or 1.80 percent, to 10,552.54 after falling more than 777 points, or nearly 7 percent, Monday to its lowest close in nearly three years. It was the blue chips’ largest point drop and 17th largest percentage drop. The percentage decline was far less severe than the 20-plus-percent drops seen in the stock market crash of October 1987 and before the Great Depression.