Have you been paying attention to shares of Packaging Corp. (PKG) ? Shares have been on the move with the stock up 6.7% over the past month. The stock hit a new 52-week high of $231.3 in the previous session. Packaging Corp. has gained 40.4% since the start of the year compared to the 9.8% move for the Zacks Industrial Products sector and the 18.5% return for the Zacks Containers - Paper and Packaging industry.What's Driving the Outperformance?The stock has an impressive record of positive earnings surprise ...