Nasdaq 100 Leaders and Laggards: APOL UAUA

The profitability of airline operators is closely linked to jet-fuel costs.

Shares of UAL declined 59 cents, or 12.8 percent, to $4.01, and set a 52-week low of $4.

Shares of network services company Level 3 Communications Inc. declined 30 cents, or 10.3 percent, to $2.62.

Shares of Steel Dynamics Inc. declined $3.88, or 10.2 percent, to $34.21.

The index, which includes 100 of the largest nonfinancial securities listed on the Nasdaq Stock Market, declined 46.56, or 2.5 percent, to 1,816.15. The broader Nasdaq composite fell 53.51 points, or 2.3 percent, to 2,251.46.

On the gaining side, shares of Apollo Group Inc. gained $8.52, or 18.4 percent, to $54.78. The University of Phoenix operator posted an adjusted quarterly profit that topped expectations.

Shares of SanDisk Corp. added $1.10, or 6.2 percent, to $18.72.

Shares of Fiserv Inc. rose $2.45, or 5.4 percent, to $47.75. The information technology provider for the financial services and insurance industries said it approved a plan to buy back up to 10 million shares of common stock.