A new reporting period for company earnings kicks into gear next week, giving investors a bit of hard data to chew on, and markets could be volatile if the price of crude oil stays north of $50 a barrel.

President Bush and Sen. John Kerry also hold the second of three debates, but if the first is any indication — with no clear winner or major stumble — they are unlikely to move markets, market analysts and traders say.

"The most important factors driving this market continue to be the price of oil, and as we approach earnings for the third quarter. Obviously that's going to be a very key driver," said Keith Keenan, vice president of institutional trading at brokerage Wall Street Access.

Aluminum producer Alcoa Inc. (AA), traditionally the first in line at the beginning of the quarterly earnings season, reports Thursday and industrial conglomerate General Electric Co. (GE) on Friday.

Standard & Poor's expects earnings to grow 13.9 percent in the third quarter, a healthy rate but off the record pace of the first half of the year when growth exceeded 20 percent.

Ed Yardeni, chief investment strategist at Oak Associates Ltd. in Akron, Ohio, with more than $8 billion under management, said he believes stocks will settle into a historical trend of 7 percent earnings growth.

Corporate earnings news could lift the market out of its sluggishness, another analyst said.

"If we have another solid earnings season, like we did for the second quarter, maybe that will give the market some motivation to post some gains," said Weston Boone, vice president of listed trading at Legg Mason Wood Walker.

All three major stock indexes ended the week higher, but for the third quarter that ended Thursday, both the Standard & Poor's 500 Index (search) and Dow Jones industrial average (search) logged their worst showing since the first quarter of 2003.

For this week, the Dow ended up 1.45 percent at 10,193. The S&P advanced 1.93 percent to 1,132 and Nasdaq rose 3.34 percent to 1,942. All three indexes turned in their highest weekly percentage gain in six weeks.

Oil prices breached $50 a barrel this week, sending stocks lower. But whenever oil slipped below the $50 psychological level, equities rose. Oil futures in New York ended at $50.12 a barrel Friday, the first time ever they settled above $50.

Boone said the price of oil is going to hang over the markets as long as crude prices continue to trade near all-time historic highs, though Keenan said anything that shows an increase oil supplies will be bullish for equities.

"Oil is closely tied with geopolitical events in the Middle East, which makes it about as volatile as it comes," said Boone. "$50 a barrel oil is not necessarily a good thing for an economy that needs to grow and expand at a steady rate."

Among key economic data, the U.S. Labor Department report on nonfarm payrolls, due Friday, is expected to show 155,000 jobs were added in September, a 10,000 increase from August. The unemployment rate is seen holding steady at 5.4 percent, a Reuters survey showed.

On Tuesday, a report from the Institute for Supply Management (search) on the monthly nonmanufacturing index, which measures the service sector. is expected to show it rose slightly in September to 58.2 from 59 in August.

Bush and Kerry are scheduled to debate in St. Louis on Oct. 8. There are no restrictions on the subject matter. A majority of financial market strategists expect Bush to beat Kerry and see a Bush victory in November as being clearly more bullish for equity markets, a Reuters poll on Friday showed.