I put on a very small short of Amazon.com (AMZN) last week (only a 1% allocation) because the market still could have potentially run to S&P 1100ish and (broken record) almost every stock is now hostage to the greater market in one massive correlation trade. With Intel reporting tonight it will take almost every tech stock on earth either up or down with it tomorrow, so I am going to cover AMZN here and revisit later. I've taken a 5% loss but again, the position size was small on purpose versus the typical 2.5-3.5% I usually do with an initial short position.
AMZN is a high beta name and when risk is on, speculators - especially of the institutional kind (along with their silicon) will run into it, so as the student body runs to their right you have to give them room as a lemming stampede can be hazardous to your fiscal health. Hence the 200 day moving average served as zilch resistance. It is increasingly a market where one wonders why to bother with individual equities as almost everything moves en masse together.