Oct. 20 (Bloomberg) -- The following companies are having unusual price changes in U.S. trading. Stock symbols are in parentheses, and share prices are as of 2:45 p.m. in New York.

Energy and oil-related shares jumped after Halliburton Co. (HAL US), the world's second-largest oilfield-services provider reported profit that beat some analysts' estimates and Oppenheimer & Co. boosted the ratings for crude producers including Exxon Mobil Corp. (XOM US).

Halliburton climbed 9.5 percent to $19.99. Exxon increased 5.9 percent to $72.05. ConocoPhillips (COP US) rose 3.7 percent to $54.47. Chevron Corp. (CVX US) added 6.6 percent to $66.48. Hess Corp. (HES US) gained 9.3 percent to $55.30. Suncor Energy Inc. (SU US) climbed 9 percent to $23.88.

Chesapeake Energy Corp. (CHK US) jumped 9.5 percent to $22.42. Cabot Oil & Gas Corp. (COG US) gained 8.2 percent to $28.25. El Paso Corp. (EP US) rallied 14 percent to $9.09. Noble Energy (NBL US) advanced 7.4 percent to $47.81. National-Oilwell Varco Inc. (NOV US) increased 16 percent to $29.75.

Anadarko Petroleum Corp. (APC US) added 7.1 percent to $35.89. Plains Exploration & Production Co. (PXP US) jumped 13 percent to $23.96. Southwestern Energy Co. (SWN US) increased 8.4 percent to $31.55. Weatherford International Ltd. (WFT US) rose 12 percent to $16.39.

American International Group Inc. (AIG US) climbed 6.2 percent to $2.23. Prudential Plc is in advanced talks with investment funds in China and the Middle East to help finance a $15 billion offer for AIG's Asian business, the Sunday Times reported, without saying where it got the information.

AT&T Inc. (T US) added 4 percent to $26.31. The largest U.S. phone company secured a $600 million contract from the Tennessee government to overhaul the state's network.

BPZ Resources Inc. (BPZ US) gained 15 percent to $9.37 and earlier rose 20 percent in the biggest intraday gain in a week. The Houston-based oil producer said it received $15 million in World Bank financing to develop its Peruvian oilfield. The funding is part of a $215 million loan program.

Brunswick Corp. (BC US) dropped 27 percent to $4.22 and earlier fell to $3.80, its lowest level since April 1983. The maker of Sea Ray yachts and Life Fitness cardiovascular machines was cut to below investment grade and is still under review at Moody's, which cited concern a contraction in consumer spending will ``put pressure on the company's dealer network.''

Deere & Co. (DE US) slumped 6.2 percent to $36.97. The world's largest maker of farm equipment was cut to ``equal weight'' from ``overweight'' at Morgan Stanley, citing the risk of lower South American sales now that the financial crisis has tightened credit in Brazil.

Developers Diversified Realty (DDR US) fell 13 percent to $14.30. The Beachwood, Ohio-based mall owner plants to reduce leverage by an unspecified amount after bankrupt California retail chain Mervyn's said Oct. 17 that it will close its 38 stores in Developers Diversified facilities.

Emcore Corp. (EMKR US) rose 20 percent to $4.44 and gained 30 percent earlier for the biggest rally since November 2004. The solar-power company may rise to $10 a share in two years if its plan to build a more efficient solar cell catches on, Barron's said, citing Chris Chaney, an analyst at Stanford Financial Group Co.

Ericsson AB American depositary receipts (ERIC US) jumped 145 percent to $7.96 and earlier gained 22 percent in the biggest intraday rally since July 2003. The world's largest maker of wireless networks said third-quarter profit beat analysts' estimates as sales and job cuts in North America surged.

General Growth Properties Inc. (GGP US) fell 9.3 percent to $5.55. The mall owner may sell up to $2 billion in preferred shares to investors including private equity and hedge funds, the Wall Street Journal reported.

HLTH Corp. (HLTH US) dropped 14 percent to $7.86 and slumped 25 percent earlier, the biggest intraday decline since October 2000. The company and its subsidiary WebMD Health Corp. (WBMD US), owner of the WebMD Web site, gave up plans to merge, citing ``uncertainty'' in financial markets and trouble finding a buyer for a second HLTH division. WebMD climbed 23 percent to $18.63.

Hasbro Inc. (HAS US) fell 8.3 percent to $27.61 and earlier slipped 9.1 percent, the steepest intraday loss since Oct. 9. The world's second-largest toymaker reported third-quarter profit margins of 55.9 percent, lower than the 57 percent estimated by Barclays Plc analyst Felicia Kantor Hendrix.

Mattel Inc. (MAT US), Hasbro's bigger rival whose quarterly profit rose less than analysts estimated, dropped 4.8 percent to $13.76.

Hormel Foods Corp. (HRL US) fell 11 percent to $30.30 and dropped 16 percent earlier for the biggest plunge since October 1987. The maker of Spam luncheon meat cut its 2008 earnings forecast to $2.03 to $2.09 a share from an earlier prediction of $2.22 to $2.28 because of higher costs and the decline in global financial markets.

Landry's Restaurants Inc. (LNY US) rose 31 percent to $11.90 and climbed 31 percent earlier for the biggest gain since at least August 1993. The owner of The Crab House and Rainforest Cafe chains said it approved a lowered, $13.50-a-share takeover offer from Chief Executive Officer Tilman Fertitta due to instability in the credit markets.

Las Vegas Sands Corp. (LVS US) lost 8 percent to $12.01. The second-biggest casino operator by market value is in discussions with banks as it considers revising the terms of the loans it's seeking for Macau projects.

Marsh & McLennan Cos. (MMC US) rose 8.3 percent to $27.75 and earlier gained 9.4 percent for the biggest intraday climb in almost a week. The second-biggest insurance broker was added to the ``conviction buy'' list at Goldman Sachs Group Inc. Insurers may raise prices as their results weaken from credit-related investment losses, which would increase fees that Marsh gets for matching buyers and sellers of coverage, Goldman said.

Midway Games Inc. (MWY US) slid 14 percent to $1.07 and earlier slumped to 96 cents, the lowest level since shares began trading in 1996. The video-game publisher controlled by billionaire Sumner Redstone posted a third-quarter loss of 70 cents a share, compared with a previous estimate of 49 cents.

NRG Energy Inc. (NRG US) rose 23 percent to $23.80 and surged 28 percent earlier for the steepest gain since it began trading in December 2003. Exelon Corp. (EXC US), the biggest U.S. operator of nuclear power plants, made an unsolicited all- stock offer to buy NRG for $6.2 billion, the second attempted nuclear power acquisition in North America in five weeks as asset prices tumble amid the credit freeze.

Exelon lost 2 percent to $53.39.

Pactiv Corp. (PTV US) fell 3.9 percent to $23.32 and earlier dropped 10 percent for the biggest intraday slide since August 2007. The maker of Hefty garbage bags was cut to ``underperform'' from ``buy'' by Merrill Lynch & Co.

Panasonic Corp. American depositary receipts (PC US) climbed 11 percent to $16.24 in the biggest intraday rise in a week. The world's largest maker of consumer electronics may beat its first-half operating profit forecast, according to an Oct. 18 report in the Nikkei newspaper. The report ``instills confidence'' in the company, Goldman Sachs Group Inc. said in a note to investors today.

Praxair Inc. (PX US) added 8.8 percent to $69.87 and earlier climbed 9.3 percent in the biggest intraday gain in a week. The largest industrial-gas producer in the Americas was raised to ``buy'' at Merrill Lynch & Co.

Prudential Financial Inc. (PRU US) lost 3.4 percent to $40.37. The second-biggest U.S. life insurer was added to the conviction sell list at Goldman Sachs Group Inc., which cited the company's ``significant exposure'' to the mortgage crisis.

Reliant Energy Inc. (RRI US) added 15 percent to $5.95 and climbed 19 percent earlier, for the biggest intraday jump in almost a week. The owner of power plants in nine U.S. states completed the sale of its Bighorn Generating Station for about $500 million. The deal should add about $45 million in pre-tax profit in the fourth quarter, the company said.

Research In Motion Ltd. (RIMM US) fell 7.8 percent to $54.41 and earlier slipped 10 percent, the biggest intraday retreat since Oct. 10. Morgan Keegan & Co. cut its sales and earnings estimates on the Blackberry phone maker, citing ``substantial worldwide damage done to the economic outlook since September.''

SanDisk Corp. (SNDK US) fell 10 percent to $13.90 and earlier dropped to $13.78, the lowest intraday price since Sept. 4. Toshiba Corp., the world's second-largest flash-memory maker, plans to buy 30 percent of production capacity at its venture with SanDisk to get cheaper access to manufacturing equipment.

Smithfield Foods Inc. (SFD US) added 12 percent to $15.28 and climbed 15 percent earlier for the biggest intraday rise since 1995. JBS SA, the world's largest beef packer, is permitted to take over Smithfield's beef-packing unit. Smithfield is the world's largest pork producer.

Synalloy Corp. (SYNL US) lost 8.4 percent to $9.82, the lowest intraday price since December 2005. The Spartanburg, South Carolina-based pipe-metal maker said third-quarter earnings fell to 20 cents a share from 36 cents in the year- earlier period. The company also said ``significant'' raw- material price increases may hurt earnings.

Syneron Medical Ltd. (ELOS US) slid 12 percent to $10 and dropped to $9.65 earlier, the lowest price since August 2004. The maker of medical products said third-quarter profit was as low as 11 cents a share, or 59 percent less than the average analyst estimate in a Bloomberg survey.

Transocean Inc. (RIG US) advanced 10 percent to $77.31 and earlier gained 10 percent, the biggest intraday rise in a week. The world's largest offshore driller was raised to ``overweight'' from ``underweight'' at Morgan Stanley, saying small startup drillers will have trouble financing projects amid the credit crunch while ``established players like Transocean'' will benefit.

TRW Automotive Holdings Corp. (TRW US) dropped 8.7 percent to $7.29 and fell to $6.90 earlier, the lowest intraday price since shares began trading in February 2004. Keybanc Capital Markets predicted a weak auto market in Europe through 2009. TRW, the world's largest maker of car-safety equipment, gets 57 percent of its revenue from the region, Keybanc said.

To contact the reporter on this story: Whitney Kisling in New York at wkisling@bloomberg.net

Last Updated: October 20, 2008 15:09 EDT