Six of the world's top central banks have taken steps to calm worried stock markets, releasing $180bn (£99bn) to lift the amount of credit available.
Leading US shares have surged, boosted by a report that the US government might announce a new plan that would tackle the financial crisis.
The news was seen positively but global stocks were volatile on Thursday amid ongoing upheaval among financial firms.
The leading Dow Jones Industrial Average added more than 400 points, or 3.86%, to 11,019.69, a rise of 560 points from its low of the day.
The Dow Jones Industrial Average index rose 350 points, on reports of a US plan to tackle the financial crisis.
Treasury Secretary Henry Paulson was looking to create a repository for bad bank debt, CNBC reported.
Ongoing uncertainty has led to fears that more top banks could collapse, as was the fate of Lehman Brothers.
World markets have been volatile in the wake of huge upheavals among banks.
Two banks in particular - Morgan Stanley and Goldman Sachs - have been singled out as vulnerable players, on fears that they will be unable to remain independent.
Since the start of the week Lehman Brothers has collapsed, the Federal Reserve has bailed out insurance giant AIG, Merrill Lynch has been acquired by Bank of America and in the UK, Lloyds TSB has merged with HBOS.
Shares in Morgan Stanley fell 21%, while Goldman Sachs, the largest remaining independent investment bank declined 13%.
US investors were boosted by the hope of broad-reaching federal intervention that might stem recent volatility, which saw the Dow Jones index fall by more than 4% on Wednesday.
Meanwhile in the UK, HBOS was acquired on Thursday by Lloyds TSB for £12.2bn, creating a giant firm.
Bush concern
Bush concern
On the markets, the Paris Cac shed 1.06% to end at 3957.86 and London's FTSE 100 ended 0.6% lower at 4880. In Frankfurt, the Dax closed 0.04% up, at 5863.42.
Earlier on Thursday, European markets had been mixed.
The Paris Cac shed 1.06% to end at 3957.86 and London's FTSE 100 ended 0.6% lower at 4880. In Frankfurt, the Dax closed 0.04% up, at 5863.42.
Bush seeks to reassure markets
Bush seeks to reassure markets
President George W Bush said he was closely monitoring the situation on financial markets and the recent actions taken by the Federal Reserve and other regulators were "necessary and important".
US President George W Bush said he was closely monitoring the situation on financial markets and the recent actions taken by the Federal Reserve and other regulators were "necessary and important".
"We will continue to act to strengthen and stabilise our financial markets and improve investor confidence," he said.
"We will continue to act to strengthen and stabilise our financial markets and improve investor confidence," he said.
The past few days have seen a number of dramatic developments on financial markets. Thursday's key events include:
Central banks from UK, US, Europe, Canada, Switzerland and Japan are releasing $180bn into their money markets. The move is the fourth such concerted effort since the onset of the credit crisis last year.
The news helped to reduce the interest rate at which banks lend to each other - a key factor behind the problems in credit markets.
Cautious investors are looking for safer places to put their money. The price of gold, regarded as a haven in troubled times, rose to $871.2 an ounce after recording its biggest one-day gain in history on Wednesday.
Lloyds TSB released details of its £12.2bn takeover of HBOS. The deals values HBOS shares at 232p each, is expected to lead to cost savings of £1bn a year and could also result in significant job losses.
Russia's main stock exchange suspended trading for a second consecutive day as the government tried to halt a sharp fall in share prices and restore confidence in the economy.
The UK's Financial Services Authority has announced steps to restrict short-selling of shares
The past few days have seen a number of dramatic developments on financial markets. Thursday's key events include:
Central banks from the UK, US, Europe, Canada, Switzerland and Japan are releasing $180bn into their money markets. The move is the fourth such concerted effort since the onset of the credit crisis last year.
The news helped to reduce the interest rate at which banks lend to each other - a key factor behind the problems in credit markets.
Cautious investors are looking for safer places to put their money. The price of gold, regarded as a haven in troubled times, rose to $871.2 an ounce after recording its biggest one-day gain in history on Wednesday.
Lloyds TSB released details of its £12.2bn takeover of HBOS. The deal values HBOS shares at 232p each and is expected to lead to cost savings of £1bn a year and could also result in significant job losses.
Russia's main stock exchange suspended trading for a second consecutive day as the government tried to halt a sharp fall in share prices and restore confidence in the economy.
The UK's Financial Services Authority has announced steps to restrict short-selling of shares.
Banks take action
Banks take action
The action taken by the central banks helped to boost confidence on European stock markets although analysts doubted it would have a long-term impact.
Earlier on Thursday six of the world's top central banks took steps to calm worried stock markets, releasing $180bn (£99bn) to lift the amount of credit available.
While the move was viewed positively, there were concerns the impact would be short-lived.
"Markets know that central banks don't own a magic bullet, otherwise they would have used it already," Sean Callow, currency strategist at investment firm Westpac.
"Markets know that central banks don't own a magic bullet, otherwise they would have used it already," Sean Callow, currency strategist at investment firm Westpac.
"And we've seen these sorts of steps before; it only addresses one of the symptoms of the underlying crisis."
"And we've seen these sorts of steps before; it only addresses one of the symptoms of the underlying crisis."
In Asia, Hong Kong ended flat at 17,632.5 after earlier falling by 7% as fears of more company failures gripped investors.
In Asia, Hong Kong ended flat at 17,632.5 after earlier falling by 7% as fears of more company failures gripped investors.
Tokyo's Nikkei share index ended 2% lower. Share indexes in Shanghai, Taiwan and India fell by between 3 and 5%.
Tokyo's Nikkei share index ended 2% lower. Share indexes in Shanghai, Taiwan and India fell by between 3 and 5%.
On Wednesday, the Dow Jones index of leading US stocks fell by more than 4%.
Market turmoil
Markets have been on a white-knuckle ride this week, with the collapse of 150-year old investment bank Lehman Brothers quickly followed by a government rescue of US insurance giant AIG.
Another investment bank, Merrill Lynch, has been taken over by Bank of America.
There has also been feverish speculation about the future of two other leading US investment banks - Morgan Stanley and Goldman Sachs. There is also uncertainty surrounding the future of Washington Mutual.
The BBC's business editor Robert Peston said that even Goldman Sachs, the pre-eminent investment bank cannot be confident it can thrive and survive as an independent.
"The credit crunch is creating a new world order in banking and finance," he said.
