If you require an example of the high risk of high valuation, the past few weeks should be all the proof you need.
The huge drops in shares of Netflix, Vertex Pharmaceuticals, Green Mountain Coffee Roasters highlight the high-flyer danger.
Arguably, those names are a little different than most. They are all small or mid caps with high valuations that generated intense debate among traders both long and short the shares. Call them the kings of volatility.
They also proof that valuation still matters.
With that in mind, we thought it better to dig a little deeper into valuations of larger, more mainstream stocks, and our crack CNBC data team dug into the S&P 500 looking for the 10 stocks with the highest PEG ratios.