Among the stock activity stories for Thursday, May 7, from AP Financial News:

NEW YORK (AP) ¿ Shares of Tenneco Inc. jumped 15 percent after an analyst upgraded the auto parts supplier and said the risks associated with automaker bankruptcies appear manageable.

NEW YORK (AP) ¿ Shares of Energy Conversion Devices Inc. plunged after the company said it plans to halt production this quarter amid uncertain near-term demand.

NEW YORK (AP) ¿ Shares of Vanda Pharmaceuticals Inc. surged after the Food and Drug Administration approved Vanda's schizophrenia drug Fanapt, following a delay of more than nine months.

NEW YORK (AP) ¿ Symantec Corp. shares fell after the security software maker reported a fiscal fourth-quarter loss on a large goodwill impairment charge and an analyst downgraded the stock.

NEW YORK (AP) ¿ Shares of Micron Technology Inc. fell after a report from Deutsche Bank downgraded the company, suggesting a recent uptick in memory chip prices could discourage customers from upgrading to higher-end chips.

NEW YORK (AP) ¿ Shares of oil and gas producer XTO Energy Inc. jumped a day after the company said its first-quarter profit climbed 5 percent and topped Wall Street estimates on rising production and lower cash costs.

NEW YORK (AP) ¿ Shares of Hot Topic fell, after the teen apparel retailer reported same-store sales rose less than analysts expected.

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