NEW YORK ( TheStreet) -- Caliper Life Sciences ( CALP), a provider of imaging and detection solutions for life sciences research, is being bought by scientific instruments provider PerkinElmer ( PKI) for about $600 million.

Caliper shares were surging 41.3% to $10.44 in premarket trading Thursday.

Homebuilder Hovnanian Enterprises ( HOV) reported a third-quarter loss of 47 cents a share, narrower than the loss of 50 cents a share that analysts, on average, were expecting.

Shares were gaining 4.9% to $1.73.

Shareholders of discount retailer Dollar General ( DG) are selling 25 million shares of the company's common stock.

Shares were falling 3.2% to $35.95.

Men's Wearhouse ( MW) expects third-quarter sales growth of 3% to 4%, which is in line with estimates. But the company gave above-consensus earnings projections for both the third quarter and full year, saying it expects adjusted earnings of 64 cents to 66 cents a share and $2.13 to $2.20 a share in the respective periods.

The company reported adjusted earnings of $58.3 million, or $1.11 a share, for its second quarter with total sales rising 22% year over year to $655 million, and same-store sales for its namesake brand increasing 10.9%.

The performance topped guidance for adjusted earnings of $1.02 to $1.05 a share, and ahead of the average estimate of analysts polled by Thomson Reuters for a profit of $1.04 a share.

Shares were tumbling 2.4% to $28.80.

General Motors ( GM) said sales in China in August rose 13.4% from a year earlier.

Shares were down 0.9% to $22.65 as general market sentiment dipped on a report that weekly initial jobless claims rose 2,000 to 414,000 hours before President Barack Obama lays out his jobs growth plans before Congress.

Smithfield Foods ( SFD), the pork processor, posted adjusted first-quarter profit of 69 cents a share, topping analysts' estimates, on strong earnings from packaged meats.

Sales in the quarter rose 7% to $3.09 billion from $2.9 billion.

Analysts surveyed by Thomson Reuters expected Smithfield to earn 67 cents a share in the quarter on sales of $3.15 billion.

Shares were up 0.6% to $22.25.

Online retail giant ( AMZN) has cut a tentative deal that would allow the online retailer to postpone collecting sales taxes from Californians for another year, The Los Angeles Times reported.

Shares were down 0.4% to $219.01.

FedEx ( FDX) is considering updating its fleet with 50 planes from Boeing ( BA) and Airbus in a deal potentially worth several billion dollars, according to Bloomberg.

Firearms manufacturer Smith & Wesson ( SWHC) expects second-quarter revenue of between $93 million and $96 million, below the average analyst estimate of $103.9 million.

First-quarter profit came in at a penny a share, beating the Wall Street breakeven target.

-- Written by Andrea Tse in New York.

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