preMarket

I figured I was so clever. My decisions to Buy & Sell my coal stock, GCE, is often based upon what BTU (a U.S. coal stock) does before the Canadian market opens (since the U.S. stock starts trading, preMarket). So I decide to investigate the correlation between these two. I look at BTU changes, from yesterday's close to today's open. About time, eh? Then I look at today's changes for GCE. I fully expected that, when BTU opens UP (from yesterday's close), the GCE would be up today ... much of the time. And what did I find? Coherent movement is lousy and correlation is even lousier! Did I mention how clever I thought I was? How I turned $100K into $323K in that contest is a miracle !