President says $30bn nationalisation plan is aimed at protecting retirees and workers.
Perino also said that the administration would seek input from the winner of the US presidential election, which will take place on November 4.
“The summit will also provide an important opportunity for leaders to strengthen the underpinnings of capitalism by discussing how they can enhance their commitment to open, competitive economies, as well as trade and investment liberalisation,” the White House said.
European leaders had pushed for a summit before the end of the year and suggested that an overhaul of the financial system should be considered.
From Tokyo, Hong Kong and Shanghai, to Frankfurt, London, Paris and New York, markets slumped on Wednesday.
European shares closed 5.5 per cent down on Wednesday, led by bank and energy stocks as investors added emerging markets ructions and waning commodity demand to their list of worries.
The FTSEurofirst 300 index of top European shares ended down at 873.30 points.
The index has lost around 18 per cent of its value so far in October and is firmly on track for its worst month on record.
In Asia, the markets dropped to their lowest levels in almost four years amid declining confidence over corporate earnings.
Shortly after opening, Wall Street stocks fell once again, despite US government efforts to get credit flowing again.
On Wednesday, the Federal Reserve, the US central bank, said it was raising the interest rate it pays to commercial banks for funds held by the reserve, in an attempt to help it raise funds to battle the credit crisis.
The Argentinian stock market also crashed by more than 16 per cent soon after opening, following the government’s decision on Tuesday to nationalise $30bn in private pension funds, saying it was necessary to protect retirees in the global financial crisis.