Pactiv Corp.'s (PTV) first-quarter net income more than doubled on higher margins, because of higher prices and lower raw-material costs, as well as tax gains.

Shares jumped 17% to $20.10 in after-hours trading as the results topped expectations and the consumer-products maker raised its 2009 guidance and predicted second-quarter earnings above analysts' average estimate. The stock through regular trading Wednesday was down 31% this year.

"Compared with the first quarter of last year, we benefited from lower raw material costs, as well as lower logistics costs, and improved productivity," said Chief Executive Richard L. Wambold. However, the recession has cut sales volumes.

Looking ahead, Pactiv now expects 2009 earnings of $2.15 to $2.25 a share on a sales decline of 10% to 12%. In January, it forecast earnings of $1.80 to $2 on a sales decline of 12% to 15%. Pactiv also expects second-quarter earnings of 54 cents to 58 cents a share. Analysts surveyed by Thomson Reuters estimated 50 cents.

Meanwhile, the maker of Hefty bags and packaging products reported net income of $91 million, or 69 cents a share, up from $35 million, or 26 cents a share, a year earlier. The latest results included a $100 million pretax pension contribution and favorable tax effects of about $50 million. In January, Pactiv forecast 44 cents to 48 cents.

Revenue dropped 5.2% to $766 million on lower volume and prices along with the stronger dollar. Analysts most recently expected $732.5 million.

Gross margin rose to 38.3% from 26% on the cost declines.

Sales fell 2% in the Hefty consumer products segment and dropped 7% in the food-service/food-packaging business.

-By Kathy Shwiff, Dow Jones Newswires; 201-938-5975; Kathy.Shwiff@dowjones.com