U.S. stocks extended losses Tuesday as Wall Street factored in a near-term rate increase and some investors predicted the Federal Reserve could boost rates as soon as September. 

The S&P 500declined 0.36%, the Dow Jones Industrial Average fell 0.42%, and the Nasdaq fell 0.42%.

Federal Reserve Vice Chairman Stanley Fischer said the U.S. labor market is "very close to full employment" in an interview with Bloomberg Television on Tuesday, adding he couldn't say whether the next interest rate increase would be "one and done."

"We can choose the pace. But we choose the pace on the basis of data that are coming in," Fischer said in the interview.

"So I don't think we know at the time we start whether it's one and done or several. It depends entirely on what happens in the economy," Fischer said.

At a speech last week in Jackson Hole, Wyo., Fed Chair Janet Yellen said the argument for a rate hike "has strengthened in recent months."

West Texas Intermediate crude oil settled lower by 1.34% to $46.35 a barrel. Investors are awaiting Wednesday's weekly reading on crude inventories, which are expected to increase.  

The Conference Board's consumer confidence index rose to 101.1 in August, topping estimates of 97.3. The index stood at 96.7 in July.

The S&P CoreLogic Case-Shiller U.S. National Home Price index rose 5.1% year over year in June, in line with May's increase.

Apple (AAPL) - Get Report shares slipped 1% after the European Union found that Ireland gave the technology giant illegal tax breaks to the tune of 13 billion euros ($14.5 billion).

Jasper Lawler, a market analyst with CMC Markets, based in London, said Apple has a long tenure in Ireland, setting up shop in the nation even before its legendary iPhone was released.

"Some of the other big tech companies have followed suit - Amazon, Alphabet's Google, Microsoft and Facebook have thousands of employees in Ireland," Lawler said to TheStreet TV. "From Ireland's perspective, that's been good for their economy."

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Potash (POT) shares rose 11.3% after the fertilizer maker confirmed it was talking to Agrium (AGU)  about a possible merger. Agrium shares rose 6%.

Shares of Hershey (HSY) - Get Report fell 11% Tuesday after Mondelez (MDLZ) - Get Reportsaid it was no longer interested in pursuing an acquisition of the chocolate and candy maker.

Mondelez offered $23 billion for Hershey last month, but was turned down.

Abercrombie & Fitch (ANF) - Get Report tumbled 21% after the retailer posted an adjusted quarterly loss of 25 cents a share, wider than analysts' expectations, and issued a soft outlook.

Shoe retailer DSW (DSW) - Get Reportslipped 10.6% after reporting a 1.2% decline in second-quarter same-store sales. The company reported earnings of 35 cents a share, beating estimates of 30 cents.

After 20 years with American Airlines (AAL) - Get Report, Scott Kirby is jumping ship to United Continental Holdings (UAL) - Get Report , taking the role of president. United shares rose 9% and American Airlines shares rose 2%.