Packaging Corp. of America ( PKG) second-quarter earnings rose 15.8% from the year-ago period, on higher pricing and volume for both containerboard and corrugated products. The company earned $32.2 million, or 31 cents a share, in the quarter, compared with $27.8 million, or 26 cents a share, a year ago. Analysts surveyed by Thomson First Call were expecting earnings of 23 cents a share. Second-quarter revenue rose 6.1% from the year ago to $551.1 million. Analysts were expecting a revenue of $532.7 million in the most recent quarter. The company expects to earn 42 cents a share in the third quarter against the analysts estimate of 37 cents a share. The Lake Forest, Ill.-based company said that higher prices and increased shipments of its containerboard and corrugated products were partially offset by higher transportation and energy costs of 7 cents a share, the impact of delaying Valdosta's annual mill maintenance outage to this year's second quarter of 2 cents a share, and other items totaling 3 cents a share. Second-quarter gross profit rose 16.9% from a year ago to $112.1 million, and gross profit margin was up 187 basis points to 20.3%. The company's shipments of corrugated products rose 2.1% from last year. Containerboard production in the quarter was up 1% from a year ago. Shares rose $1.79 early Wednesday to $22.80.