Shares of Nucor ( NUE) were among the NYSE's losers Tuesday, sinking 8% after the steelmaker projected fourth-quarter earnings well below Wall Street's expectation.

The company expects fourth-quarter earnings of $1.05 to $1.15 a share, compared with $1.09 a share a year earlier. Analysts polled by Thomson First Call project earnings of $1.44 a share. "The fourth quarter earnings will be less than anticipated because spot market prices for sheet and bars are lower than expected and scrap prices have not decreased as much as anticipated, both factors which have negatively impacted our margins," Nucor said. Shares were trading down $4.72 to $59.63.

Shares of Best Buy ( BBY) slid 6% after the consumer electronics retailer posted disappointing third-quarter earnings. For the quarter ended Nov. 25, the company earned $150 million, or 31 cents a share, on revenue of $8.47 billion. Analysts polled by Thomson First Call expected earnings of 35 cents a share and revenue of $8.42 billion. During the year-earlier quarter, the company earned $138 million, or 28 cents a share, on revenue of $7.34 billion.

Best Buy blamed the earnings miss on competitive pressure, which hurt margins. Shares of the company were trading down $3.37 to $50.55. Shares of rival Circuit City ( CC) were down $1.55, or 6%, to $23.39, on concerns that it may see similar margin troubles.

Spartech ( SEH) slid 16% after the plastics maker posted mixed fourth-quarter results and gave a lower-than-expected forecast for fiscal 2007. For the fourth quarter ended Oct. 28, the company earned $8.6 million, or 27 cents a share, on revenue of $375 million. Excluding items, earnings were $12.1 million, or 37 cents a share, a penny above analysts' forecast. Spartech's revenue totaled $375 million, below Wall Street's projection of $378 million. A year earlier, the company reported adjusted earnings of $7.9 million, or 24 cents a share, on revenue of $366 million.

Spartech sees fiscal 2007 earnings of $1.55 to $1.60 a share, below analysts' average projection of $1.62. "This guidance reflects a full year of recently completed restructuring activities and the current weaker market demand conditions being experienced in the automotive, building and construction, and heavy truck markets," the company said. Shares were trading down $4.69 to $25.43.

Shares of Dollar General ( DG) rose 2% even after the retailer posted a hefty third-quarter loss on charges. For the quarter ended Nov. 3, Dollar General recorded a loss of $5.3 million, or 2 cents a share, compared with a year-earlier profit of $64.4 million, or 20 cents a share. Sales rose to $2.21 billion from $2.06 billion, missing Wall Street's expectation for a top line of $2.26 billion.

Dollar General's results included charges totaling $79.2 million related to the company's recently announced restructuring plan, which involved closing hundreds of stores and eliminating a type of inventory model. The company's shares were up 26 cents to $15.44.

Shares of Scotts Miracle-Gro ( SMG) rose 5% after the lawn and garden products company said it plans to return $750 million to shareholders through a special dividend and share buyback plan. Scotts plans to buy up to $250 million of its own shares through a Dutch auction, which is likely to begin in January. The balance of the program will be paid in the form of a one-time cash dividend.

The plans require the recapitalization of the company's balance sheet and include a new credit facility of $2.1 billion. "By comfortably increasing debt levels, we will reduce our total cost of capital and simultaneously improve our return on capital," Scotts said. "As a result, we will further increase the economic value we are creating, which is what all shareholders expect."

For fiscal 2007, Scotts sees adjusted earnings growth of 11% to 13% and revenue growth of 8% to 10%. Shares were trading up $2.74 to $53.57.

The NYSE's volume leaders Tuesday were Ford ( F), up 2 cents to $7.26; Best Buy; Corning ( GLW), down 51 cents to $19.81; Texas Instruments ( TXN), up 4 cents to $29.33; Pfizer ( PFE), down 8 cents to $25.07; Time Warner ( TWX), down 4 cents to $21.29; Citigroup ( C), down 98 cents to $51.90; EMC ( EMC), down 31 cents to $12.91; and General Electric ( GE), down 1 cent to $35.21.

Nasdaq's heavy movers included ON Semiconductor ( ONNN), up 1 cent to $7.51; Sun Microsystems ( SUNW), up 1 cent to $5.74; Nuvelo ( NUVO), up 28 cents to $4.33; Microsoft ( MSFT), down 14 cents to $29.40; Oracle ( ORCL), down 18 cents to $17.89; Cisco Systems ( CSCO), down 2 cents to $27.09; Intel ( INTC), down 5 cents to $20.65; Yahoo! ( YHOO), up 47 cents to $26.96; Apple ( AAPL), down $2.23 to $86.52; and Sirius Satellite Radio ( SIRI), up 1 cent to $3.82.