“An investment operation is one which, upon thorough analysis, promises safety of principal and an adequate return [emphasis mine]. Operations not meeting these requirements are speculative.” – Ben Graham, The Intelligent Investor

As to “safety of principal,” stocks are currently 67% overvalued suggesting 40% potential downside just to return to average historical valuations:

valuation-indicators-averagevia dshort.com

And as for “adequate return” stocks are currently priced to return about 2% per year over the next decade:

wmc140210avia John Hussman

How do you like them apples (and by “apples” I mean “risk reward equation”)?