NEW YORK (CNNMoney) -- The bull market on Wall Street enters its fourth year this week and investors are wondering how much higher stocks can go.
Stocks ended modestly higher Friday, capping a mixed week for the major indexes. The Dow Jones industrial average eased slightly over the last five trading days. The S&P 500 and the Nasdaq edged up modestly last week.
Over the long term, however, stocks have been marching higher: Friday marked the third anniversary of the current bull market.
The S&P 500 and Nasdaq have more than doubled in value from bear market lows on March 9, 2009. And the Dow is up more than 97%.
But some investors worry that a sharp rise in oil and gas prices could shock the global economy and stifle the stock market.
"Recent activity data have brought further signs that global growth is recovering from its recent dip," said Simon Hayes, an economist at Barclays Capital, in a research report. "At the same time, however, the threat of a jump in oil prices is likely to keep financial markets and policymakers watchful, even as euro risks recede."
While prices have eased in recent days, U.S. crude oil futures are up more than 8% this year amid fears that tensions between Iran and Western powers could disrupt supplies from the Middle East.
The week ahead brings key reports on the U.S. economy, a meeting of the Federal Reserve and the promise of a final approval for Greece's second bailout.
Economists expect a report Tuesday to show overall retail sales rose in February on gains in automobile and gasoline sales.
Meanwhile, reports on consumer and producer prices for February are expected to show modest increases in inflation, reflecting the rise in oil and gas prices.
Other items on the calendar include regional manufacturing reports, business inventories and data on export and import prices.
The Federal Reserve will hold its second policy meeting of the year on Tuesday.
The central bank is not expected to announce any changes to interest rates or major policy measures, but it may offer a slightly brighter assessment of the economy following upbeat reports on the job market.
In Europe, finance ministers from the 17 nations that use the euro on Monday are expected to authorize the release of a second round of loans for Greece from the eurozone bailout fund.
Greece announced Friday that private sector creditors will take part in a historic restructuring of the government's debt, which was the final condition of its €130 billion bailout program from the European Union and International Monetary Fund.
On Tuesday, the IMF is expected to decide how much it will contribute to the bailout. IMF director Christine Lagarde suggested Friday that the fund could chip in €28 billion over four years.
The bailout for Greece could remove a major source of uncertainty that has been hanging over the market this year, although analysts say the nation's debt problems are far from over.
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