The wait for Friday's speech from Federal Reserve Janet Yellen left investors hesitant on Thursday. 

Stocks broke into the red by mid-afternoon Thursday after a choppy morning riding the flatline. The S&P 500 closed down 0.13%, the Dow Jones Industrial Average slid 0.17%, and the Nasdaq slipped 0.11%.

Fed members headed to Jackson Hole, Wyo., for their closely watched summer summit. Prominent central bankers, finance ministers and economists from around the world meet annually to discuss economic trends and monetary policy action.

Investors are most eager to hear from Fed Chair Janet Yellen, who will deliver a widely anticipated speech on Friday. Her comments will provide important context to the markets' outlook for interest rates.

"We expect the Chair to carry the torch and set a tone that suggests a greater likelihood of a September hike than the market is pricing in," BNP Paribas analysts wrote in a note. "We expect a positive assessment of the state of the economy before Ms Yellen gets into tools that the Fed has at its disposal to combat any economic downturn."

A number of Fed members have signaled that steady improvement in the U.S. economy warrants a rate hike sooner than later. Kansas City Fed President Esther George said growth in the job market and inflation forecasts indicate "it is time to move" in an interview with Bloomberg Radio Thursday morning. Separately, Dallas Fed President Robert Kaplan, a voting member of the Federal Open Market Comittee, told CNBC that the arguments for a rate hike are progressing.

The chances of a September rate hike currently sit at 21%, according to CME Group fed funds futures. A rate hike in December has better chances at 41%.

Orders for long-lasting goods in the U.S. in July increased 4.4%, the Commerce Department reported Thursday. Orders for civilian and defense aircraft drove July's strength. Core durable orders increased 1.6%. The better-than-expected improvement signaled a recent downturn in manufacturing activity is coming to a close.

The number of new claims for unemployment benefits fell 1,000 to 261,000 in the week ended Aug. 20, the Labor Department said Thursday. The less-volatile four-week average declined by 1,250 to 264,000. Jobless claims have remained below the 300,000 mark for 77 straight weeks, the longest streak since 1970.

In earnings news, HP (HPQ) - Get Report was flat as fourth-quarter forecasts disappointed. The printer company expects current-quarter earnings no higher than 37 cents a share, short of consensus estimates of 41 cents. Weak sales of its printers weighed on projections, even as notebook sales offset softer demand.

HP earned 48 cents a share on revenue of $11.9 billion in its third quarter. Analysts expected profit of 44 cents a share on revenue of $11.47 billion.

Guess? (GES) - Get Report jumped 22% after it exceeded earnings estimates but missed sales forecasts in its recent quarter. The fashion brand earned 14 cents a share in its second quarter, 7 cents higher than expected. Revenue inched 0.2% lower to $545. million, coming in $5.5 million below expectations.

Williams-Sonoma (WSM) - Get Report  reduced its full-year forecast, with chief executive officer Laura Alber citing a "more cautious consumer." The home-goods retailer reported a 4.8% decline in comparable-brand sales at Pottery Barn, its largest brand by sales. Williams-Sonoma cut its annual earnings estimates to $3.35 to $3.55 a share, down from $3.50 to $3.65 a share.

Tiffany (TIF) - Get Report moved 6% higher after reporting a mixed second quarter. The jeweler earned 84 cents a share, up from 81 cents in the year-ago quarter and 12 cents higher than estimates. Revenue fell short, falling 6% to $932 million and just falling shy of consensus. Worldwide same-store sales declined 8%.

Mylan (MYL) - Get Report moved lower after taking steps to reduce the cost of its EpiPen in the wake of criticism from Democratic presidential candidate Hillary Clinton. The drugmaker said it would take "immediate action" to make its allergy medicine more accessible, including doubling the eligibity for its patient assistance program and reducing the cost of the treatment. The cost of the treatment has increased fivefold since 2007.