There are legitimate concerns that the entire market is way overdue for a correction.  As we saw almost 2 years ago, no stock is a sure bet when there's a sell-off event, no matter how positive the news flow is.   It's the reality of the markets.  

My friends in portfolio management are not as concerned about a near term correction, but the longer term prospect of what will happen when interest rates rise (even though that could be years still).