I trade commodity futures for a living, and have never had this problem until today. I opened up my electronic account statement tonight, and found that I was holding a very sizeable (for my account anyway) position in March corn. The trade showed to have been executed today at the market close, through my electronic trading platform. However, I never made this trade. At first I thought I had made an error and accidentally entered this MOC order, so I double checked my "executions" and "orders" files on my platform to make sure. Sure enough, no orders were ever placed on the platform, and it shows no execution ever took place. What is also odd is that this trade is for double the amount of contracts that I normally submit at one time (as per my position limit sheet provided to my broker's RM department). Apparently even the RM guys didn't catch this trade, which leads me to definitely conclude there was no way it was entered from my platform. Luckily I called my broker and he was still around, and he confirmed that the trade did happen on Globex and not the floor, and he also confirmed it originated from my IP address (not sure how they determined that but thats what he said). I am the only one who has access to my computer, and I was trading all day. Obviously its too late to get the trade busted, and its not a big deal as far as P/L goes unless corn gaps huge on the open, but it does have me concerned about how this happened and if it could happen again. Has anyone else had a similar experience?? If so how did you resolve it / what ended up being the issue?? Thanks in advance guys.