NEW YORK — Wall Street staged a dramatic turnaround today, shooting higher in the last half-hour of trading after word that a bailout plan for troubled bond insurer Ambac Financial could be announced next week. The major indexes ended a week of choppy trading mixed.

CNBC reported shortly before the closing bell that a plan to help shore up the finances of Ambac Financial Group Inc. could be announced Monday or Tuesday. Ambac shares jumped on the report and finished up $1.48, or 16 percent, at $10.71.

The market's turnaround came after nearly two full days of selling. The Dow Jones industrial average had been down nearly 130 points, but by the close, showed a 225-point reversal from its lows of the session.

"There's probably some validity to the rumors," said Jim Herrick, manager of equity trading at Baird & Co., referring to traders' speculation about Ambac. "With the overall financial crunch we've experienced, this brings new confidence in the sector."

The Dow rose 96.72, or 0.79 percent, to 12,381.02.

Broader stock indicators also moved higher. The Standard & Poor's 500 index rose 10.58, or 0.79 percent, to 1,353.11, and the Nasdaq composite index rose 3.57, or 0.16 percent, to 2,303.35.

For the week, the Dow edged up 0.27 percent, while the S&P 500 rose 0.23 percent and the Nasdaq lost 0.79 percent.

The market's early decline followed a sell-off yesterday that left the Dow down more than 140 points, or 1.15 percent. Investors worried about a weaker-than-expected reading on regional manufacturing from the Federal Reserve Bank of Philadelphia as well as another drop in the Conference Board's monthly index of leading economic indicators.

Bond prices reversed alongside stocks. The yield on the 10-year Treasury note, which moves opposite its price, rose to 3.80 percent in late trading from 3.78 percent late yesterday. The dollar was mixed against other major currencies, while gold prices fell.

Light, sweet crude for April delivery rose 58 cents to settle at $98.81 a barrel on the New York Mercantile Exchange amid concerns about possible supply disruptions and cold weather.

The day's late reversal appeared to ease some of Wall Street's concerns about the prospects for the financial sector and the overall economy after several weak economic readings. The reports arriving in recent weeks have raised questions about whether the Federal Reserve will be able to fend off a recession. There have also been more urgent fears the U.S. may be entering a period of stagflation — when stalling growth accompanies rising prices — for the first time since the 1970s.

As occurred Wednesday and again late today, investors at times set aside those concerns and snapped up stocks either to cover bets that stocks would fall or amid genuine, if tentative, optimism that officials from the Fed to other parts of the government could help right the economy. Wednesday's gains followed a quiet start to the week Tuesday — markets were closed for Presidents Day Monday — and came after minutes from the Fed's last meeting indicated the central bank plans to lower interest rates as needed and look past some gathering concerns about inflation.

Wall Street's bursts of optimism haven't proven long-lasting. Investors remain concerned that the economy could be so weak that rate cuts, which take months to work their way through the economy, won't stave off a further slowdown. A government-backed plan to aid bond insurers could help boost confidence in the bond market, where a lack of confidence has crimped the flow of money.

The Fed's next rate-setting meeting is scheduled for March 18. Policymakers lowered key interest rates a half-point to 3 percent on Jan. 30, following an emergency three-quarter point cut the previous week.

Ryan Detrick, strategist at Schaeffer's Investment Research in Cincinnati, said that among the reports due next week, investors will be looking to readings on producer prices — a key measure of inflation — as well as on consumer sentiment. He noted that recent consumer confidence figures, which have been weak, added to Wall Street's concerns that hesitant consumers could pare their spending.

A pullback among buyers is an unwelcome prospect for investors as consumer spending accounts for more than two-thirds of U.S. economic activity.

Meanwhile, Fed Chairman Ben Bernanke will be testifying about the economy during two appearances on Capitol Hill.

In corporate news, Merrill Lynch lowered its ratings on government-sponsored lenders Freddie Mac and Fannie Mae to "sell," contending the companies face continued headwinds amid the credit crisis. Freddie Mac fell $1.14, or 4.1 percent, to $26.61, while Fannie Mae declined 27 cents to $28.72.

Software maker Intuit Inc. fell $2.74, or 9.2 percent, to $27.05 after posting a 21 percent decline in its second-quarter profit late Thursday.

Advancing issues outnumbered decliners by about 3 to 2 on the New York Stock Exchange, where consolidated volume came to 3.46 billion shares, compared with 3.55 billion seen Thursday.

The Russell 2000 index of smaller companies slipped 0.85, or 0.12 percent, to 695.43.

Overseas, Japan's Nikkei stock average closed down 1.37 percent. Britain's FTSE 100 fell 0.74 percent, Germany's DAX index closed down 1.43 percent, and France's CAC-40 slid 0.71 percent.