The reason is quite simple: short selling. MR short ratio now sits at 14. This a huge value. In the last few days the 7% drop was most likely an attempt by MM to stir some panic so they could cover their short positions at a minimum loss. Since MR has been over $30 for quite some time and most of these shorts positions were initiated at sub-$30 values, meaning most are at a loss right now.

Now today comes the earnings date announcement. MR is very likely to beat since every export port in China has reported a 40% increase in medical device export. This will make short sellers jumpy and if the short ratio was 1 or 2, covering would be very easy, but at 15 we have a lot of them and eventually some will be nervous and cover at a loss. Because keeping a short at post-earnings will simply be such a huge gamble.

The upwards motion is happen in either of 2 ways: gradual all the way to earnings date or abrupt right after earnings, although I predict the latter. One way or another it will come.