Biggest Microsoft surge in 4 years lifts Dow

A big jump in Microsoft helped lift the Dow Jones industrial average Friday.

Microsoft had its biggest gain in four years after CEO Steve Ballmer said he will retire. Ballmer took the helm of the software company from founder Bill Gates in 2000. The company has struggled to adapt as consumers switch from desktop computing to mobile devices

The giant software company is part of the 30-member Dow and its surge contributed more than a third of the index's advance.

The Dow closed up 46.77 points at 15,010.51. The index closed down 0.5 percent for the week and is 3.2 percent lower for the month. The Standard & Poor's 500 index edged up 0.4 percent to 1,663.50. The Nasdaq composite rose 0.5 percent to 3,657.79.

Stocks have sagged in August on concerns that the Federal Reserve will start to pull back on its economic stimulus. The Fed has been buying $85 billion in bonds every month to hold down long-term interest rates and encourage lending.

Some investors are using the summer slump as an opportunity to buy stocks at less expensive prices, said Joe Bell, a senior equity analyst at Schaeffer's Investment Research. Stocks climbed to record highs at the start of the month. "People are buying this pullback right now."-- AP