NEW YORK (TheStreet) -- Clothing chain Urban Outfitters (URBN) reported second-quarter earnings that fell 21% to $56.7 million, or 35 cents a share, as profit margins shrank.

The company beat analysts' expectations for earnings of 32 cents a share, boosting the shares in after-hours trading Monday. However, the stock was giving back those gains, plunging 10.4% to $26.61 in premarket trading Tuesday.

Solar panel maker Evergreen Solar ( ESLR) has filed for Chapter 11 bankruptcy as it caved under stiff competition from cheaper Chinese products.

Share were dropping 9.4% to 16.3 cents.

Private-equity firm Carlyle Group is in exclusive talks to buy drug company Pharmaceutical Product Development ( PPDI) for possibly as much as $4.3 billion, according to Bloomberg.

Pharmaceutical Product Development shares were popping 3.5% to $32.60.

Warren Buffett's Berkshire Hathaway ( BRK.B) has initiated a small stake in the discount retail chain Dollar General ( DG), and now has a $51 million position.

Dollar General shares were popping 3.3% to $33.24.

BP ( BP) has replaced its head of strategy as the company tries to find ways to revive its share price following last year's $41 billion Gulf of Mexico oil spill, Bloomberg reported.

Shares were down 3.2% to $40.34.

Wal-Mart ( WMT) reported its ninth consecutive decline in U.S. same-store sales, but second-quarter earnings and total revenue topped forecasts, sending shares up 2.9% to $51.45 in premarket trading Tuesday.

The retail giant earned $1.09 a share on revenue of $108.6 billion, receiving a boost from Sam's Club and its international unit. Analysts were calling for a profit of $1.08 a share on revenue of $108.28 billion.

Shares of Agilent Technologies ( A) were falling 2.8% to $36.45 after the measurement company forecasted adjusted net income of 79 cents to 81 cents a share on revenue of $1.74 billion to $1.76 billion in the current quarter. Analysts were estimating earnings of 81 cents a share on revenue of $1.75 billion.

Third-quarter revenue came in at $1.69 billion, roughly in line with the Wall Street consensus target of $1.66 billion. The company posted third-quarter profit of 77 cents a share vs. the average analyst estimate of 73 cents a share.

Home Depot ( HD), the No. 1 home-improvement retailer, raised its earnings outlook for the fiscal year and said second-quarter profit rose 14.3% on a rebound in its seasonal business.

Home Depot shares were rising 2.5% to $32.23.

Home Depot earned $1.36 billion, or 86 cents a share, in the second quarter, up from year-earlier earnings of $1.19 billion, or 72 cents a share. Analysts surveyed by Thomson Reuters expected Home Depot to earn 83 cents a share.

Computer company Dell ( DELL) is expected to report second-quarter profit of 49 cents a share after the markets close Tuesday vs. last year's profit of 32 cents a share. Shares were down 0.3% to $15.45.

Branded food products company J.M. Smucker ( SJM) cut coffee prices by 6% for the majority of its brands including Folgers, as the costs for green coffee fell.

-- Written by Andrea Tse in New York.

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