Six reasons that the risk of a stock-market selloff is rising. Here's what investors should be doing.

By Jamie ChisholmMany markets are priced for perfection, warns Longview EconomicsKeeping an eye on Wall Street risks - which are on the rise.Investors wary of the "cover curse" - where an individual's, a sports team's or a company's appearance on a magazine's front cover signals a peak - may be rat…