NEW YORK (TheStreet) -- Stocks moved like a roller-coaster on Thursday, fluctuating through the day as investors struggled to get a for clear direction ahead of next week's Federal Reserve meeting. 

That meeting is looming large as stocks appear to be trading less on fundamental than competing forecasts about whether the Fed will raise interest rates.

Benchmark indexes opened at the flatline, soared by lunchtime, and deflated by the end of the day as the S&P 500   finished 0.5% higher while the Dow Jones Industrial Average added 0.47%, and the Nasdaq gained 0.8%. 

The outcome of the Fed's Sep. 16-17 meeting remains anyone's guess. Some economists believe the Fed will hike rates for the first time since 2006 after their two-day meeting next Thursday, arguing that a tightening labor market and improving economy no longer warrant crises-level rates. 

"Our baseline scenario is that the Fed will deliver a rate hike but package it in a dovish message. The dots are likely to show only one rate increase this year, signalling that the initial move will be followed by a long pause," said Aneta Markowska of Societe Generale. "If there is no hike, we would expect the accompanying message to be somewhat hawkish, implying a strong possibility of an October lift-off."

Others argue a further decline in crude oil prices and a slowdown in China will likely push a rate hike out to later in the year. 

"Despite resiliency in the domestic economy, some risks previously on the Fed's radar have become real," BNP Paribas analysts said of global developments in a note. "We expect no action on rates, a dovish set of economic and interest rate projections, and for the Chair to use her press conference to keep expectations of a hike 'later this year' alive."

The majority of investors think a September rate hike unlikely. The Fed funds futures are currently pricing in a probable hike at less than 25%, according to CME Group.

Crude oil moved higher on Thursday despite an increase in inventories over the past week. The U.S. added 2.6 million barrels to crude stockpiles last week, nearly triple an estimated increase of 900,000 barrels. West Texas Intermediate crude closed 4% to $45.92 a barrel to reverse Wednesday's losses.

Major oilers including Exxon Mobil (XOM) , Chevron (CVX) , Halliburton (HAL) and Royal Dutch Shell (RDS.A) moved higher, while the Energy Select Sector SPDR ETF (XLE) jumped 0.58%.

Apple (AAPL) shares were more than 2% higher as investors assessed the company's revamped Apple TV and updated iPhones. During its annual product event on Wednesday, Apple announced that its redesigned set-top box will feature voice commands using voice-activated personal assistant Siri and a touch interface. The company also unveiled a larger iPad, which will measure 12.9 inches on the diagonal, and a stylus for the iPad called Pencil which will retail for around $99.

Amazon (AMZN) climbed 1% after announcing plans to discontinue its Fire Phone after selling through its inventory. The smartphone had received poor reviews upon its release in 2014 and has since seen weak demand.

Other major tech stocks were also higher including Google (GOOGL) , Microsoft (MSFT) , Qualcomm (QCOM) and Cisco (CSCO) . The Technology SPDR ETF (XLK) gained 1%.

Trading in Avon (AVP) was briefly halted after a price surge triggered a circuit breaker. Shares jumped more than 12% before being halted. Once trading began again, shares fell 9.5%. The company is reportedly holding talks with private-equity funds for a new round of investments, according to The Wall Street Journal.

Weekly jobless claims fell 6,000 to 275,000 in the week ended Sept. 5, an indication the labor market continued to tighten. The result was as economists had expected. The average number of new claims for unemployment benefits over the past month rose 500 to 275,750, according to the Labor Department.

Import prices fell 1.8% in August, their biggest decline of 2015, as oil prices remained low and the high U.S. dollar made foreign goods cheaper. Over the past year, import prices have dropped 11.4%, their largest decline since 2009.

In earnings, Lululemon (LULU) reported a better-than-expected second quarter, benefiting from an increase in sales and a greater number of stores. The athletic apparel company reported comparable-store sales rose 6% over the quarter, while total revenue jumped 16% to $453.01 million.

XPO Logistics (XPO) fell after it agreed to buy Con-Way (CNW) for $3 billion. XPO will become the largest freight transportation company in the U.S. following the deal. XPO shares were down 11.1%, while Con-Way soared 33.8%.

Hard-drive developer Seagate (STX) fell 1.8% after announcing plans to cut 1,050 jobs, or 2% of its work force, as it commits to a restructuring program. The job cuts are expected to save $113 million annually.