The stock market regained its footing Friday, but the modest rebound wasn’t enough to keep the U.S. market from having its worst week since 2008.

The Standard & Poor’s 500 index rose 0.6 percent Friday, and the Dow Jones industrial average was up 37.65 points, 0.35 percent, to 10771.48. The Nasdaq advanced27.6 points, or 1.12 percent, by closing bell.

However, that followed four straight sessions in which stocks declined, as fears deepened about Europe’s debt crisis, the weak U.S. economy, and a new Federal Reserve policy move that investors viewed as having only a limited effect on boosting growth.

The S&P index was down 6.5 percent for the week.

The rebound on Friday reflected speculation that European leaders gathered in Washington for meetings of the International Monetary Fund and World Bank this weekend might reach agreement on new measures to try to instill confidence and avert a default by Greece on its debt.

During the day, Wall Street zigzagged between positive and negative territory for most of the trading session following a two-day period that knocked more than 6 percent off the value of U.S. stocks.

In Asian markets, there were declines of up to 2 percent, despite attempts by the Group of 20 finance ministers, who are gathered in Washington, to assuage global fears. The G-20 ministers pledged late Thursday to do everything they can to keep the sovereign debt crisis in Europe from spreading.

But investors are increasingly skeptical of the ability of political leaders, particularly in Europe, to chart a course forward that does not involve Greece defaulting on its debt and the resulting risk of failure of many banks across the continent.

European Central Bank governing council member Klaas Knot was quoted Friday in the Dutch daily Het Financieele Dagblad as saying that a Greek default “is one of the scenarios. I’m not saying that Greece will not go bankrupt,” Knot said, though he added that bankruptcy was “not necessary.”

In addition, growing concern about China’s slowing economic growth, and a decision by Moody’s to downgrade eight Greek banks, stoked the uncertainty that has fueled a losing week.

Investors are fleeing from risky stocks toward assets viewed as safer, particularly U.S. Treasury bonds; the government needed to pay only 1.73 percent Friday to borrow money for a decade, the lowest level on record.

European markets were down in afternoon trading, but recovered before closing. Germany’s DAX rose 0.6 percent; France’s CAC 40 was up 1 percent and Britain’s FTSE advanced 0.5 percent.

In Asia, Hong Kong’s Hang Seng index fell 1.4 percent Friday, after plummeting nearly 5 percent a day earlier. South Korea’s Kospi took the greatest hit Friday, dropping 5.7 percent — losses driven largely by new fears of an economic slowdown in China, Seoul’s largest trading partner. Australia’s S&P/ASX 200 finished the day down 1.6 percent. The Shanghai Composite fell 0.4 percent.

Japan’s markets were closed for a holiday.

The rough trading day in parts of Asia came after the International Monetary Fund downsized its projections for Chinese GDP growth, lowering its forecast both for this year and in 2012. The report suggested a slowdown for the manufacturing industry — bad news for the export-reliant nations who depend on China to buy their commodities.

The statement late Thursday from the G-20 leaders provided a modest safety net for Asian and European trading and offered hope that U.S. stocks might regain some of the losses from Wednesday and Thursday.

The statement, pledged to support Europe’s troubled banks, emphasizing their commitment to “a strong and coordinated international response to address the renewed challenges facing the global economy.”

Investors this week have been moving toward safe haven currencies, particularly the yen and the U.S. dollar, leading to massive slumps for emerging market currencies. The value of the South Korean won fell again on Friday for the fifth consecutive day. South Korea said it will step up monitoring of financial conditions and take action against any “irregular” movement in the foreign currency market.

Harlan reported from Tokyo; Birnbaum reported from Berlin. Staff writer Sarah Halzack contributed to this report.