Nov. 6 (Bloomberg) -- The following companies are having unusual price changes in U.S. trading. Stock symbols are in parentheses, and share prices are as of 1:15 p.m. in New York.

Energy companies slumped as crude oil fell to a 19-month low and natural gas declined for the first day in five. Southwestern Energy Co. (SWN US) fell 13 percent to $32.08. El Paso Corp. (EP US) lost 16 percent to $7.98. National-Oilwell Varco Inc. (NOV US) declined 12 percent to $26.48. Chevron Corp. (CVX US) decreased 5.9 percent to $70.49. Exxon Mobil Corp. (XOM US) retreated 5 percent to $69.99.

Activision Blizzard Inc. (ATVI US) rose 11 percent to $12.23 and earlier climbed 13 percent for the biggest intraday gain since Oct. 13. The video-game maker formed in July when Vivendi SA bought a controlling stake in Activision Inc. said it plans to buy back as much as $1 billion of its stock.

Ambac Financial Group Inc. (ABK US) tumbled 23 percent to $1.55 and fell earlier to $1.46, the lowest since Oct. 10. A credit-rating downgrade of the bond insurance company that has slumped 93 percent this year forced it to post collateral and terminate contracts.

Amdocs Ltd. (DOX US) fell 17 percent to $19.50 and slid 23 percent earlier for the biggest intraday decline since June 2002. The world's largest billing and customer-service software provider reported fiscal fourth-quarter profit that fell short of the average analyst estimate and forecast first-quarter sales and earnings that trailed analysts' projections.

AnnTaylor Stores Corp. (ANN US) tumbled 26 percent to $8.95 and earlier fell to $8.77, the lowest since December 2000. The U.S. clothing retailer that targets women 25 to 55 said third- quarter profit will be less than it previously projected because of a ``dramatic deterioration'' in the financial markets and the economy.

Ansys Inc. (ANSS US) rose 10 percent to $29.24 and climbed 18 percent earlier for the biggest intraday gain since September 2001. The software developer forecast profit of at least $1.68 a share this year. That exceeded the average estimate of $1.60 from analysts in a Bloomberg survey.

Big Lots Inc. (BIG US) slumped the most in the Standard & Poor's 500 Index, falling 23 percent to $5.28. The largest U.S. seller of discontinued goods said third-quarter earnings will be ``near or slightly below'' the low end of its forecast after sales missed its projection.

Blackstone Group LP (BX US) fell 14 percent to $7.60. The manager of the world's largest buyout fund said it had a third- quarter loss of $502.5 million as the financial crisis eroded the value of its private-equity investments. Blackstone had been expected to break even, based on the average estimate of seven analysts in a Bloomberg survey.

Conseco Inc. (CNO US) jumped the most in the Russell 1000 Index, climbing 32 percent to $2.33. The Carmel, Indiana-based life insurer said it has no need to raise capital.

Continental Resources Inc. (CLR US) fell 15 percent to $24.92 and earlier slumped 18 percent for the biggest intraday retreat since Oct. 22. The U.S. oil and gas explorer reported third-quarter sales and profit that fell short of analyst estimates. Earnings of 62 cents a share were 19 percent lower than the average projection, according to Bloomberg data.

Developers Diversified Realty Corp. (DDR US) fell for a second day, losing 15 percent to $9.67. The owner and manager of 720 shopping centers yesterday announced the suspension of a $350 million mixed-use project near Detroit.

FTI Consulting Inc. (FCN US) tumbled 29 percent to $41.09 and earlier dropped 33 percent, the most since January 2004. The company, which advises businesses on litigation, bankruptcies and restructuring, reduced its full-year earnings forecast and will delay an initial public offering of its technology business until next year.

Global Crossing Ltd. (GLBC US) rose 17 percent to $7.29 and climbed 24 percent earlier for the biggest intraday gain since January 2005. The telecommunications provider that survived one of the biggest U.S. corporate bankruptcies told analysts in a conference call that the rest of 2008 will be ``strong.''

Hertz Global Holdings Inc. (HTZ US) slid 12 percent to $5.88 and earlier fell as much as 23 percent, the most since Oct. 9. The second-largest U.S. rental-car company said third-quarter profit fell 89 percent as businesses and consumers cut back on travel. Hertz said it won't meet its 2008 earnings forecast.

Hot Topic Inc. (HOTT US) jumped 8.8 percent to $6.54 and earlier rose 20 percent for the biggest intraday gain since November 2006. The teen clothing and music retailer said in a statement of preliminary results that it earned as much as 17 cents a share in the fiscal third quarter, topping its previous estimate.

LandAmerica Financial Group Inc. (LFG US) dropped 32 percent to $4.95 and fell earlier to $4.71, the lowest level since October 1991. The third-biggest U.S. title insurer postponed the release of third-quarter results, saying it needs ``additional time to complete the preparation and review of its financial statements.''

Las Vegas Sands Corp. (LVS US) tumbled 38 percent to $7.22 and earlier slid 44 percent for the biggest loss since its December 2004 initial public offering. The casino company whose shares fell as much as 95 percent from their October 2007 peak said it may be in default of some loans if it can't raise capital, threatening its ability to keep operating ``as a going concern.''

McDermott International Inc. (MDR US) slumped 29 percent to $10.99 and earlier fell 30 percent, its biggest intraday drop since August 2003. The energy-services company that's expanding its nuclear-fuel business reported third-quarter profit that was 47 percent less than the average analyst estimate, according to Bloomberg data.

News Corp. (NWS/A US) fell 16 percent to $8.26, and earlier lost 19 percent, the biggest drop since at least November 1994. The media company controlled by Rupert Murdoch said it expects fiscal 2009 profit to decline from a year ago, reversing its earlier projection for an increase of as much as 6 percent.

OM Group Inc. (OMG US) gained 12 percent to $21.78 and jumped 21 percent earlier for the biggest intraday advance since February 2003. The world's largest cobalt producer posted a 48 percent jump in third-quarter profit, boosted by acquisitions, higher metal prices and a tax credit.

SRA International Inc. (SRX US) fell 27 percent to $13.86 and tumbled 30 percent earlier for the biggest intraday decline since May 2002. The provider of information technology services to the federal government reduced its 2009 earnings forecast, projecting profit of as much as $1.22 a share. Analysts, on average, estimated $1.34, according to a Bloomberg survey.

Syniverse Holdings Inc. (SVR US) plunged 43 percent to $10.27 and sank 46 percent earlier for the biggest intraday loss since February 2005. The provider of technology services to mobile- phone companies was cut to ``neutral'' from ``outperform'' by Robert W. Baird analyst William Power, who cited ``mounting'' revenue disappointment next year.

THQ Inc. (THQI US) dropped 28 percent to $4.70 and earlier fell to $4.37, the lowest since June 2000. The video-game publisher said it will close five studios and cut 250 jobs to reduce costs and focus on fewer, higher-quality titles. The company also lowered its sales and profit forecast for the fiscal year ending in March.

Toyota Motor Corp. American depositary receipts (TM US) fell 17 percent to $66.21 and earlier slumped 19 percent for the steepest decline in 18 years. The world's second-largest automaker forecast the biggest drop in profit in at least 18 years as a global slump cripples auto demand and gains in the yen erode the value of overseas sales.

Other automakers also dropped. General Motors Corp. (GM US) slipped 12 percent to $4.90. Ford Motor Co. (F US) lost 6.2 percent to $1.96. Honda Motor Co. ADRs (HMC US) slumped 15 percent to $22.41. Nissan Motor Co. ADRs (NSANY US) declined 9.4 percent to $8.76.

Tyco Electronics Ltd. (TEL US) dropped 12 percent to $16.77 and earlier slid to $15.77, the lowest level since being spun off by Tyco International Ltd. in June 2007. The world's biggest maker of electronic connectors said fiscal fourth-quarter profit fell 55 percent on restructuring costs and forecast a ``significant'' drop in sales and earnings this period.

Warnaco Group Inc. (WRC US) lost 32 percent to $17.47 and dropped 37 percent earlier for the biggest intraday slide since February 2003. The maker of Calvin Klein jeans and Speedo swimwear reduced its earnings forecast for the year, predicting profit of as much as $2.65 a share, excluding some items. The company previously expected to earn at least $2.80.

Whole Foods Market Inc. (WFMI US) climbed the most in the Standard & Poor's 500 Index, gaining 6.2 percent to $10.94. The largest natural-foods grocer said it received a $425 million equity investment from Leonard Green & Partners LP.

To contact the reporter on this story: Lu Wang in New York at lwang8@bloomberg.net

Last Updated: November 6, 2008 13:56 EST