Wall Street tumbled 1 percent on Tuesday, as fears over the federal government shutdown continued to weigh on U.S. stocks.

After the bell, shares of Alcoa Inc. (NYSE: AA) jumped as the aluminum producer beat Wall Street estimates and reported fiscal third-quarter earnings of 11 cents a share, excluding one-time items, on sales of $5.8 billion, compared with a loss of 13 cents a share on revenue of $5.8 billion a year earlier.

Analysts polled by Reuters had expected the company to report quarterly earnings of 9 cents per share on revenue of $5.7 billion. In addition, the aluminum producer affirmed its 2013 global aluminum demand growth forecast of 7 percent.

“Our performance this quarter shows our repositioning of the Company is on the right path,” said Klaus Kleinfeld, Alcoa Chairman and Chief Executive Officer. “We continued to build our value-add businesses, capturing demand for innovative material solutions across multiple markets.”

Shares of Alcoa rose 1.51 percent to $8.06 in after-hours trading.

Yum! Brands, Inc. (NYSE: YUM) missed Wall Street forecasts and issued third-quarter earnings of 85 cents a share, excluding one-time items, on revenue of $3.5 billion, compared with a profit of $1 per share on revenue of $3.6 billion in the year-ago quarter.

Analyst had expected the parent company of KFC and Pizza Hut to report quarterly EPS of 92 cents on revenue of $3.5 billion. The company added that it expects full-year earnings to decline at a “high-single to low double-digit rate,” sending shares tumbling after the close.

The company revised its full-year outlook and added in the report that “Given lower-than-expected China sales and a higher-than-expected full-year tax rate, the Company now estimates a high-single to low-double-digit full-year EPS decline versus prior year, excluding Special Items.”

David C. Novak, chairman and CEO, said in the report, “Despite the disappointing third-quarter performance, I remain as confident as ever in our ability to deliver strong, sustainable growth in the years to come.”

Shares of Yum! Brands, Inc. plunged 7.35 percent to $66.40 in extended-hours trading.  

On the earnings calendar for Wednesday, notable companies include Family Dollar Stores Inc. (NYSE: FDO) and Costco Wholesale Corporation (Nasdaq: COST).