SLP - Price Fixing? Collusion?

Hello, I'm a total noob dicking around with stocks and I'm trying to figure out what happened to me this morning.

I purchased 75 shares of SLP a few weeks ago at $6.38. Yesterday I saw a huge gain (8%+ to $7.30) and was feeling pretty good about myself.

So after the market closed, I decided to put a stop limit in @6.86 to protect my profits. To my surprise, I saw that the order filled this morning around 9:30 am. Checking the chart, it looks like SLP dropped momentarily to 6.67 at 9:30am, causing the order to be executed. Shortly thereafter, the price bounced back up within minutes. WHY DID THIS HAPPEN? I'm convinced there's something fishy going on here. Like some sort of price fixing and/or collusion. Can anyone shed some light?

-Edit- Anyone has any advice for how to avoid this in the future? Should I just never use stop limit orders? Also, is it possible for someone with enough shares to temporarily bring down the price and essentially steal other shareholders earnings through their stop order limits?

Submitted September 04, 2015 at 04:48PM by cybergrime http://ift.tt/1PQLEdg