Shares of Packaging Corp of America (PKG) tumbled 6.29% in after-hours trading on Tuesday, despite the company reporting first-quarter earnings that surpassed analysts' expectations. The sharp decline suggests that investors may be focusing on factors beyond the headline numbers.

For the first quarter of 2025, Packaging Corp reported adjusted earnings per share of $2.31, beating the IBES estimate of $2.21. The company's net income came in at $203.8 million, also surpassing the estimated $197.3 million. Sales for the quarter reached $2.141 billion, exceeding the projected $2.108 billion.

While the company's financial performance appeared strong on paper, the significant after-hours drop indicates that market participants may be concerned about other aspects of the report, such as future guidance or industry outlook. It's also possible that despite beating estimates, the results fell short of even higher market expectations, especially considering that Truist Securities had recently lowered its price target on PKG from $265 to $238. Investors will likely be closely watching for any additional insights or commentary from the company's management in the coming days to better understand the reasons behind this negative market reaction.