Packaging Corp. of America reported first-quarter earnings Monday that were slightly short of Wall Street forecasts, although they represented the Lake Forest company's best-ever first quarter.

Net income for the big packaging concern was $32.1 million, or 31 cents a diluted share, up from the year-ago quarter's new of $31.2 million, or 30 cents a share.

Sales moved up 3.3 percent to $577.5 million from $559.2 million a year ago.

Packaging Corp.'s latest per-share earnings, released after the market's close Monday, landed a few pennies short of the 34 cents that analysts had been anticipating.

While stronger pricing for container board and corrugated products helped profits, the company said, those benefits were "offset in large part" by sharply higher costs for energy, as well as higher costs for raw materials and other factors.