Trade school: Parabolic move

The ETF for home builders went parabolic last week, mostly because of an earnings blow-out from DR Horton (DHI). This chart is one to watch to see how dangerous parabolic moves can be. ITB faded intraday after stretching well above its upper Bollinger Band (BB). The BBs define an expected price range. So when price goes well above the upper-BB, the stock, ITB in this case, is "stretched" and due for a cooling period if not an outright pullback. I am watching this one closely as I am a perma-bull on housing.