News

NEW YORK (MarketWatch) -- Shares of the following companies made noteworthy moves in the U.S. stock market Wednesday:

Advancers

Aetna Inc. shares gained 5.2%, with a slew of health insurance companies advancing one day after Senate Majority Leader Harry Reid, D-Nev., said Congress may not make a year-end deadline to pass health-care legislation.

Other managed-care companies on the move included Cigna Corp. , which finished up 5.2%, and UnitedHealth Group Inc. shares, which ended 3.6% ahead.

Ambac Financial Group shares surged 35% to $1.5 after the bond insurer reported a $2.19 billion quarterly profit. Read full story.

Big 5 Sporting Goods Corp. shares climbed 2.7% after the specialty retailer reported profit gained 80% in the third quarter. .

Biocryst Pharmaceuticals Inc. shares gained 8.5% after the company said a partner had filed for approval to market its flu drug in Japan. .

DaVita Inc. shares advanced 6.5% after the largest U.S. operator of dialysis clinics said its profit jumped 18% in the third quarter. .

MBIA Inc. shares gained 7.5% after rival bond insurer Ambac Financial Group reported a third-quarter profit of $2.19 billion. .

Merck & Co. shares advanced 6.4% after the drug giant closed its $41.1 billion acquisition of Schering-Plough Corp. .

Pulte Homes Inc. shares rose 3.5% after the home builder's quarterly results disappointed, but the company said its industry is stabilizing. Read full story.

Decliners

American International Group shares fell 7.7%. Read Financial Stocks.

Baker Hughes Inc. shares lost 5.9% after the supplier of drill bits and other equipment for oil and gas rigs said quarterly net income fell 87%. Read full story.

Genworth Financial Inc. shares declined 7.4%.

Goodyear Tire & Rubber Co. shares dropped 6.1%.

Hartford Financial Services Group shares declined 5.3% after the insurer late Tuesday reported a quarterly loss. See detailed report.

Molson Coors Brewing Co. shares dropped 8.5% after the company reported third-quarter earnings. Read full story.

True Religion Apparel Inc. shares fell more than 24% after the company's third-quarter profit fell below expectations. Read Retail Stocks.

Unum Group shares dropped 5% after the disability insurer's late Tuesday quarterly report. .

Zions Bancorp shares fell 5.2%.