James A. Cederna, Director at MINE SAFETY APPLIANCES CO (MSA), sold 2,500 shares at $42.81 ($107K) on 2012-05-16, disclosed to the SEC on 2012-05-17.
Seasonal sale ($107k) by Director — this insider has traded MSA in May in at least three consecutive prior years. Pattern-driven, low signal.
Negative factors outweigh the positive ones.